Honda NSX, more specificly - NSX-R (aka Type-R) no doubt about it -
subzero.
Obviously not everyone here understand the true worth of this car, so let me add my 2c.
Apart from Senna there were another two F1 drivers involved in testing and development of this car - S.Nakajima and B. Rahal. Their effort was critical in making the car as it is now.
Being lightweight, mid-engined rwd car with ultra-rigid, ultra-light aluminum monocoque chassis, wide wheel base, advanced aerodynamics, low CoG and great weight destribution, Honda NSX-R is the pure example of what a real sportscar should be. It's NA 3 litre V6 engine is the high revving one (so quick response and flat power curve as the result) coupled with the 6 speed manual gearbox with short gear ratios - all together makes it perfect for circuit racing, - that's what NSX was meant to be, and that's what it's all about. The weak point of the car is the JDM stricted power output and brakes which seem to perform poorly but only when braking hard to standstill otherwise they aren't an issue.
Those of you who watch Best Motoring should have a good image of this car's capabilities. "Cornering machine" - that's how all of the racers who appear in BM call the NSX. Now really, it's cornering perfomance is really impressive. It goes around the corners faster than, well, basicly anything. Hell, it even laps Tsukuba a tad faster than 911 GT3 and last-gen 911 Turbo (Tiptronic S ver). It stays competitive against the modern supercars which have twice as much power.
Here're some vids with NSX-R competing against some supercars.
Motegi battle, Part 1:
Motegi battle, Part 2:
Motegi battle, Part 3:
Too bad Honda haven't competed with NSX much anywhere apart from Japan. It entered LeMans two or three times, the best result was the 1st place in GT2 class - but that's it. As for Japan, NSXs are now dominating Super GT championship and
ARTA NSX is the current champion.