The luxury SUV is a kind of car that's polarizing among enthusiasts. They're big and tall, and a lot of people don't like how they look. Quite a few people also think they're not as practical as traditional luxury sedans or station wagons. Love them or loathe them, these cars are here to stay. They sell well, and they can be one of the best choices for anyone who wants a comfortable and practical daily driver. They can also be a great choice for anyone who wants a one-car solution that has performance as well as comfort and practicality.The car we're going to discuss here definitely lives up to that one-car solution brief. It's got supercar-rivalling performance, wrapped in a luxury SUV body. It's also a bit of a sleeper, and it's more of a great used bargain than people think! Luxury SUVs Are Relatively New In The Car Market BentleySUVs have been around in some shape or form since the 1980s, at least. Luxury SUVs, however? They've been around for less time than a lot of us have been alive. While you could consider the Range Rover to be the first luxury SUV, it was in a class of one for quite a while. It wasn't until the emergence of proper rivals like the Cadillac Escalade, the Lincoln Navigator and the more upmarket Lexus-badged versions of the Toyota Land Cruiser when luxury SUVs became a very real segment in the car market.Most luxury SUVs are designed for pure comfort. Some, though, are intended to be as fast as proper performance machines. Some enthusiasts aren't keen on them. But, they've proven to be very popular with buyers who've got money to burn and want the perfect one-car solution for everything they could want. Some Luxury SUVs Are Fast Enough To Hold Their Own Against Pure-Bred Performance CarsLamborghiniWithin that niche of luxury SUVs, there's a sub-niche that has performance as a main focus as well as luxury. These big, high-performance monsters often have very powerful engines. Quite a few of them use hybrid assistance to make them even more powerful, and there are even some that are fully electric. Whatever the case may be, they've all carved out a name for themselves as SUVs that can seriously rival sports cars and supercars with their performance. The Audi RS Q8 Is A Performance SUV That's As Fast As A Modern SupercarThe Audi RS Q8 is a high-performance SUV that barely ever gets talked about. But, it's possibly one of the best on both the new and used markets. It's a high-performance variant of the Audi Q8, and has the understated appearance of that model as a result. Don't let that fool you, though. This big, luxurious, practical hauler is a proper sleeper car, with enough power and performance to rival a modern supercar. While it may only have a top speed of 149 mph, it can do the 0-60 mph sprint in just 3.8 seconds. It's also got plenty of power (591 horsepower), thanks to a 4-liter twin-turbocharged V8. Of course, because it's a V8, you get that fantastic noise too! It Shares A Platform With The Bentley Bentayga, The Porsche Cayenne And The Lamborghini Urus ABT SportslineWhile you may not have heard of the Audi RS Q8 before, you've definitely heard of other cars it gets many of its components from. The platform the RS Q8 is based on is shared with the ultra-luxurious Bentley Bentayga, the incredibly bold Lamborghini Urus and the most recent internal combustion version of the Porsche Cayenne. All three of those cars also use the same 4-liter twin-turbo V8. The Lamborghini Urus uses it exclusively, while it appears in some higher-performance models of the ICE-powered Porsche Cayenne and the pure ICE Bentley Bentaygas.All that parts sharing goes a long way to explain the Audi RS Q8's sleeper status. Under the skin, it's basically a Lamborghini Urus. If the awesome performance of the Urus appeals to you but you don't want the crazy and divisive looks that come along with it, the RS Q8 could be a fantastic solution. A New Performance Model Was Introduced With The 2024 Facelift AudiLike many cars do, the Audi Q8 got a mid-life facelift in 2024. That included a re-work of the RS Q8. Part of the re-work of the RS Q8 was the addition of a new "Performance" model. This version gets a significant power bump from the regular RS Q8, taking its output up to 630 horsepower and 627 lb-ft of torque. That also drops the 0-60 mph time down to 3.4 seconds, and brings the top speed up to 160 mph. While that means it's still lacking in the top speed department compared to a modern supercar, its acceleration is now even more competitive with them. It's Not As Expensive As You Might Think On The Used MarketAudiThe Audi RS Q8 is a very expensive car brand new. That's even when you take into account that it's significantly cheaper than the cars it's a sibling of that use the same engine. A brand-new Audi RS Q8 will cost you around $138,300 in the US - expensive, but still a fraction of the price of a V8-powered Porsche Cayenne or Bentley Bentayga. If you look on the used market, though, the Audi RS Q8 is actually a bigger bargain than you might have expected. As just one example, a 2021 RS Q8 sold for $72,000 a couple of years ago. That value will have definitely significantly gone down since then, too, as luxury SUVs often depreciate heavily. For comparison, a Porsche Cayenne GTS from the same model year sold for for $79,000 in February this year, while a Bentley Bentayga V8 from the same model year sold for $117,500 in April this year. You could expect to pay even more than that for a 2021 Urus, as one example sold for $155,000 in December 2025. Compared to all of those examples of its siblings, the Audi RS Q8 really feels like the best value for money out of the bunch.Sources: Audi, Bentley, Bring A Trailer, Lamborghini, Porsche