What's the most important aspect of a car? As an onlooker, it may be the way the body lines are designed with elegance or aggressiveness, or perhaps it's the sound the exhaust makes when the driver punches it. As a car owner though, those things are indeed important, but the interior itself will typically become the focal point to define a car's ownership experience.

Interior design within cars has come a long way for sure, packing plenty of tech inside, and using advanced and more efficient production methods to give cars a better interior for the price. But, at the end of the day, most cars are made for a mass market and compromise the interior to make it acceptable for the most amount of people.

What if you've got plenty of money to spare though, and want an interior that compromises nothing in achieving its vision? Enter Carlex Design, based in Poland, Carlex is a design studio that specializes in building unique custom cars but are most well known for their incredible custom interiors that are wilder than your wildest dreams.

From a dinky little Fiat to the greatest in supercars, Carlex's portfolio of custom car interiors is varied and large but maintains a level of consistency when it comes to the impeccable detail and luxury they bestow cars with. So, read on, to see 10 of the craziest interiors made by Carlex that we've seen so far:

10 McLaren 720S

Via Carscoops

When it comes to high-end interiors, few people would complain about the McLaren 720. Designed with high quality, high tech, driver-focused layout, the 720S' interior can even be customized to your wishes under McLaren's MSO program. Yet, MSO has its limits in terms of just how bespoke things can get.

Via Carscoops

Naturally, that's where Carlex steps in, going beyond the already high-end bespoke interior options the 720S has available from McLaren. As mentioned, everything here is a custom job with intense attention to detail, and a simple glance should make that plainly evident.

From the custom leather patterns and colors to the fact that said leather is wrapped around every surface, Carlex Design proved just how luxurious they can make a car with this 720S. As for the color, it may not be a favorite for everyone, but for fans of old-school luxury cars, it rings true to the days when a Burgundy leather and velour interior was the pinnacle of style and class.

9 Fiat 126P

Via Carlex Design

When giving a custom overhaul to a car's interior, starting with a supercar like the 720S is ideal, as said interior will already have a luxurious and high-end design. The Fiat 126P is the farthest thing possible from a supercar, and has one of the most barebones stock interiors possible, yet, Carlex managed to transform one with a surprising amount of luxury.

Via tuningblog.eu

This was no ordinary project though, as firstly, the Fiat 126P is a Polish-made car and icon of Poland's motor industry, and secondly, this one was custom made for legendary actor Tom Hanks. Having visited Hungary a few years ago, Tom Hanks had made several humorous posts on Twitter leaning up against examples of the little Fiat parked on the street with the caption "I am so excited about my new car!"

Catching the attention of Monika Jaskólska, a resident of the Polish town where the 126P was built, a fundraising event was organized to buy Tom Hanks a 126P of his own - but one ended up being given for free by an anonymous donor. Restored and sent off to Carlex Design, the humble 126P received a fully custom leather interior that manages to make the simple metal box look like a genuine luxury car. Decked out with accents like typewriter keys as switches, the Carlex Design Fiat 126P is the best one of these cars has ever looked inside and out.

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8 Ferrari 488

Via Carscoops

As cool as Tom Hanks' custom Carlex Fiat is, the work Carlex Design does on supercars is on a whole other level of amazing - case in point, their custom blue Ferrari 488.

Via Motor1

Like the McLaren 720S, the Ferrari 488 has a sporty, high-end interior to begin with, but lacks when it comes to truly wild and luxurious customization options. Of course, Carlex is no stranger to such out of this world custom options, and their design for this 488 is indeed out of this world.

One thing you'll notice on Carlex Design interiors are the intricate and stunning looking seat patterns, the ones here are some of their finest work in that regard. Emphasized by sporty Alcantara, the blue leather looks absolutely sumptuous, and the flowing lines with gold contrast inserts give it a visual pop that adds just the right amount of flashiness. All in all a gorgeous cockpit design, the Carlex Design 488 adds incredible luxury on top of the driver-focused interior design.

7 Mini Countryman "Steampunk Edition"

Via BMW Blog

Proving their work isn't just limited to high-end supercars and luxury machines, and further proving their mastery of custom interiors, this Mini Countryman was overhauled over the course of 9 months to become a completely unique "steampunk" creation.

Via BMW Blog

A style based around the whimsical copper and clockwork motifs from steam-powered machines of the past, the Steampunk Mini Countryman is filled with the stuff. Immediately evident is the copper-colored leather upholstery, done up with Carlex' masterful stitching, but a closer look reveals a plethora of show-stopping details.

Within the steering wheel lies a skeletonized clockwork motif, and at the base of the seats is a set of actual clockwork movements embedded into the seats themselves. Further accents include an actual copper coating on the air vents, gauges, and steering wheel, as well as rich wood paneling on the floor and back of the seats. The Steampunk theme may be off-putting to some, but this Mini Countryman is one of Carlex' craziest custom jobs.

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6 Mercedes-AMG G63 "Steampunk Edition"

Via CarBuzz

If you like the steampunk aesthetic of the Countryman but want it to be done in a subtler color palette on a more luxurious and powerful machine, then the Carlex AMG G63 Steampunk is the perfect custom car for you.

Via CarBuzz

A 5,200-hour job to complete, the Steampunk AMG G63 is dripping with refined luxury, as well as artistic mastery that's simply jaw-dropping. Starting with the exterior, the Steampunk AMG G63 has a fully copper roof with a steampunk style work of art engraved into it by jewelers - immediately setting the car apart as a work of art in itself.

On the inside though, rich brown leather dominates each and every angle you look at. That leather would be luxurious enough on its own, but making it even more spectacular are a walnut wood floor, and rose gold and copper coatings on practically every piece of trim. It doesn't even stop there though, as covering the headliner and various leather pieces throughout the interior are hand engraved designs continuing the theme of the steampunk art on the roof - now that's attention to detail.

5 Mercedes-AMG G63 "Yachting Edition"

Via Carlex Design

The Steampunk AMG G63 is a downright superb example of Carlex' work, and so are their other AMG G63 interiors. Showcasing the lighter spectrum of their work is another G63, this time paying tribute to luxury yachts.

Via Carscoops

Offered in a choice of color schemes, including off-white leather with Alcantara (pictured above), or Cognac leather with white accents (pictured on top of entry), either looks absolutely opulent, fusing the already luxurious G63's interior with inspiration from a yacht's interior.

Aside from the rich leather seats, and their excellent stitch-work is a yacht-like wooden floor, and a leather headliner embossed with a compass rose motif and lines running across the interior. As with the Steampunk Edition, almost every surface is either wrapped with leather or given further refinement and custom touches, making it as close to a road-going yacht as possible.

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4 1990 Mercedes Benz G-Class "Vintage"

Via carscoops

Carlex's G-Class interiors stand out as simply stunning, which should be fairly evident by now. But, what if you like the G-Class, but prefer the vintage models to the new ones? Well, Carlex fulfilled that exact wish and worked their magic on one from 1990.

Via Motor1

It's not sumptuously elegant like the Yachting Edition G63, but instead, the G-Class Vintage goes above and beyond by sticking strictly to a true vintage theme, showing what a Carlex G-Class may have looked like if it were made in 1990.

Covering every surface they possibly could with leather, only small bits like the switches make it evident that any plastic was used to make this G-Class. Also using ample amounts of wood, the real star of the show here is the seats. As mentioned, one of Carlex' hallmarks is intricately stitched, luxurious leather seats, and the G-Class Vintage is a prime example of that. Made with two contrasting shades of leather, the design is both modern and retro at the same time, perfectly continuing the two-tone distressed leather theme within the rest of the interior.

3 Mercedes-AMG GT R Pro "Tattoo Edition"

Via Autoevolution

This AMG GT R's interior may be a bit extreme for some people's tastes, but as an example of how crazy Carlex can go when customizing a car, it stands out as one of their most awesome creations.

Via Autoevolution

Fitted with the previously mentioned suite of premium materials all throughout, the Tattoo Edition AMG GT R gets all the sumptuous luxury Carlex gave to its Mercedes-AMG brothers, like the G63, but then offset it with a wild in-your-face tattoo theme.

Much like the Steampunk Edition AMG G63, the Tattoo Edition GT R uses leather engraving to leave its mark. Consisting of classic tattoo motifs like rose flowers, skulls, and angel wings, many bits of trim throughout the interior are given hand engraved designs. Again, those tattoo-style designs may not be to everyone's taste, but they're are downright awesome regardless of your opinion when you consider the level of detail, workmanship, and luxury that Carlex puts into their interiors.

RELATED: Deutsche Viper: The AMG GT R Is Germany’s Super-Serpent

2 Nissan GTR

Via thesupercarblog.com

Unlike supercars like the McLaren 720S and AMG GT R, the Nissan GTR's interior is rather function-oriented, leaving luxury and high-end appointments aside for the sake of being an affordable supercar-killer. Of course, transforming that tech-heavy interior into something high end is no problem for Carlex though.

Via: thesupercarblog.com

Following the Nissan GTR's video game kind of spirit, Carlex bestowed this one with an interior that matches that spirit beautifully. While their more intricate designs are best defined as stunning or elegant, their work on this GTR is cool and sporty first and foremost.

While stunning in the level of detail, the design here is reminiscent of modern video game character design, having an embossed pattern and color scheme that's reminiscent of the armor from Mass Effect. Not that that's a bad thing, as all of the leather and carbon fiber touches come together to give this GTR an appropriately awesome interior that elevates the whole car with it to another level of coolness.

1 Toyota Tacoma

Via Motor1

While Carlex' bread-and-butter tend to be high-end luxury and sports cars, they aren't the kinds of people to shy away from making something different, and this workhorse turned luxury off-roader is certainly something different.

Via Motor1

A rugged and reliable, but in no way luxurious truck, the Carlex custom Tacoma appears to be based on the 2nd generation of the truck, which spanned 2005 to 2015 and had a basic interior that wasn't anything special to look at or sit inside. Tweaking the exterior as well, Carlex transformed the unremarkable truck into a forest-themed off-road beast with some serious all-terrain performance parts and a shockingly nice interior.

Immediately hitting off that forest theme is the green suede headliner and its contrast against the green leather - creating an outdoor feeling on the inside of the truck. Present is the luxurious slathering of leather that Carlex is known for, as well as the patterned seats which look both rugged and luxurious at the same time. While the hardcore off-road builds may be more capable, the Carlex Tacoma lets you hit the trails in luxury and looks great doing it.

NEXT: These Are The Most Badass Custom Trucks We've Seen