Don't only think fastest or most powerful,
but consider handling/drivablity/dynamics etc,
and just plain good fun.

For me it was a modified BMW made (supercharged)
Cooper S - JCW....(ie) dump wheels, suspension
brakes, exhaust, Replace with LW forged rims/Pirelli,
Bilstein, Remus, Brembo, upgrade pulley, high-flow
airbox,, add Chip... laugh

The M3 was way less fun in comparison.

Moral of the story -
good things come in small packages.

-Bulletproof and Waterproof don't mean Idiotproof.