A friend of mine recently told me that the latest "evolution cars" and high end spin-offs are neither exciting nor superior anymore. He illustrated this with the not really top rated Audi TT RS, but there are many other disappointing examples like the latest Mitsubishi Lancer Evo or Subaru Impreza.
Let's go back and look at some older offsprings and famous evolution and homologation specials. For example the unforgettable BMW M3 E30 in 2.3 and 2.5 liter disuise. BMW built this car as the basis for motorsports and when you drive one of these you can fell this is true.
Or take the Porsche 924 Carrera GTS. A true racing car with road registration. Hotter than the GT which already was a pretty exciting car.
One of the most famous homlogation specials probably was the Porsche Carrera RS 2.7 liter, built between 1972 and 1973. It was planned to build 500 of them, but demand was so big that more than 1'300 were built and the racing career was a long lasting one with many special versions built on top.
Ferrari build many evolution and homologation cars, i.e. the 250 SWB or the F40. All of them have been competitive and attractive as well.
What all of these have in common are a good amount of race pedigree and steep price developments. A very good evolution model of the M3 for example can easily fetch almost the price as "new", Porsche 924 Carrera GTS have already gone beyond that. And we all know how much a good Ferrari 250 SWB or even an F40 is worth today. The Porsche Carrera RS 2.7 is traded higher than USD 200'000 today, 4-5 times of the price for the new car.
So, as a summary, true homologation specials and evolution models are cars without compromise, designed to win on the track and to offer a minimum amount of comfort and convenience anywhere else. Collectors love these things and even when the car is not competitive compared to modern sports cars, driving one of them is awesome and very rewarding.
So, if you plan to buy a Audi TT RS, maybe you reconsider, buy a normal TT and an M30 E30 on top.