supercar engines last as long as regular engines, the main difference between them and regular cars is that their maintenance is a lot more rigorous and expensive. many owners don't use them everyday despite their ability because they most times have better everyday cars with softer more comfortable suspensions that wont rattle them around as much. Jay Leno even has a Lamborghini Countach (Lamborghini is not known for reliability especially before audi bought them) and has over 70,000 miles (112,000 kms) which is very high for a supercar especially an old v12 lamborghini. with an audi r8 you can expect it to last an extremely long time because they already know how to deal with that engine. (it was based on the 5.2L v10 from the gallardo which in turn was based on the engine used in the S6 and S8 cars which are meant to be actual everyday cars.