Yes, really. There are downsides.
Even though it came stock with an inline-six engine, the last generation Toyota Supra is capable of producing more than 1,000 hp, with the proper modifications of course. Rob Ferretti, aka Super Speed Rob, owns a heavily modified Supra that makes about 1,000 hp, which is in and of itself pretty darn awesome. However, there are downsides, mainly the expenses involved. More simply put, it's not cheap to crank things up to 1,000 ponies, as Rob likes to point out.
Remember, a stock Supra (or just about anything else stock) can't handle that much of a power increase without reinforcing things, such as the clutch and suspension. You don't want the car to literally rip in half. Sticky tires are also essential in order to put the horsepower down, and they aren't for bargain shoppers.
And then there are the nearly constant mechanical checks involved. Because of so many modifications, you're making the car more complex and it requires additional attention. All of these things add up. Then again, only something like 10 to 15 percent of Supras actually have at least 1,000 hp, so owning one also means you're automatically a member of a pretty exclusive club.