Supercars ~ Aston Martin V12 Vantage, Bugatti Veyron, Jaguar XJ220...
Sports Convertibles ~ Jaguar XKR, Porsche 911 Carrera Cabrio, Rolls Royce Phantom DHC...
Coupes/GT's ~ Nissan 350Z, Audi R8 4.2 V8 Quattro, Audi TT R...
Sports cars ~ Caterham 7 Super Light R500, Vauxhall VX220 Turbo, Porsche Boxster...
4X4s/MPVs/Estates ~ Audi RS4, Lamborghini LM002, Range Rover V8 Supercharged...
Big Saloons ~ Audi RS6, BMW M5, Jaguar XJR..
Sports Saloons ~ Audi S4, Honda Accord Type R, Subaru Impreza WRX...
Hot Hatches ~ Audi S3, Honda Civic Type R, VW Golf R32...
Super Minis ~ Citroen C2 VTS, Mini Cooper, Skoda Fabia VRS...
All the above is from "Evo Magazine ~ The Knowledge". The Nissan 350Z & the 370Z are Coupes/GT cars and that's what class they fall into. If you have a 350Z Roadster then that falls into the "Sports Convertibles" class. I concur with this way of looking at vehicle types regardless of cost & performance.
I do not agree that a Subaru Impreza in any form can be compared to a 350Z or 370Z ~ they are imo totally different types of vehicles.