Originally Posted by Vinny

^^ this.
Like I said, it's a matter of opinion. With enough money, you can make almost any car do anything. You can be stubborn and say "no Z will ever beat any supercar", but the fact of the matter is that a civic is not in the same "classification" as a Z, but don't be surprised to see a modified one spanking you around a track. Same goes for a Z and an Aston Martin, or Ferrari, or whatever. You may never want to classify a Z as a supercar, but it CAN outperform supercars with enough investment.

There are almost not limitations in the tuner world these days. You can have a custom tranny made, swap a gtr engine forged with nice big turbos, suspension mods, stripped, nice big brakes, etc.. (you get the idea) What are you left with? A lighter, faster, smaller GTR.
What you need to understand is that cars are platforms these days.