in order of funness..
e30 m3
e39 m5
r35 GTR
e30 m3 was the best overall just pure sports car, you could drive the absolute shit out of it and the harder you drove the better it felt, never felt anything like that in a street car.
the m5 was just insanely solid and confidence inspiring, getting the tail out on 80 mph corners was easy to do, just a little extra steering input or an aggressive lift and the tail was out and super easy to control.
the GTR was just insanely fast. you just floor it between corners and suddenly your going 150+
honorable mention goes to a 400+whp evo 9, had a built engine with an itty bitty turbo and it had an amazing powerband, it had brand new coilovers as well as a lot of suspension components and none of it was set up so it was insanely sketchy, it would understeer then snap into huge oversteer completely unpredictably, i have no idea how the car was as bad as it was but it was easily the most exciting thing ive driven because of it.
driven a lot of track/race cars that are obviously much better but that shouldnt count.