GTR has always been referred to as a supercar. Supercar looks, performance, focus, and notoriety.
Addressing the M3 as a supercar might be a bit much but the R8 and 911 Turbo are probably ok.
Great looking GTR there, OP. I like how you mentioned it makes you feel like you've got nothing to prove. This car is not a stepping stone, you're finally there. Now you can just sit back and enjoy it. When you're happy with your own ride like that, it doesn't matter what anyone says.