ZR1 is over 100K so its not an option.
FYI: the 2012 Z06 with the the Z07 option is faster than the 2012 GT-R around "The Ring". That is with a professional driver, which none of us are. The new 2013 GT500 is going to be priced in the sub 60k range and is the highest HP V8 ever mass produced with 650HP from the factory, AMAZING bang for the buck street cruiser/highway on ramp killer. With all that said, I would pick the GT-R. It does EVERYTHING really really well. Catless Y-Pipe + Tune = 10 second 1/4 miles passes, extremely fast around a road course, great handling and braking, nice interior, ect.
GT-R is the clear choice if you are ok with paying supercar maintenance for fluids and brakes. Also aftermarket parts have a "GT-R Tax" with the cheapest exhaust around $3900. For the average guy, and even the "good drivers" the GT-R will be the best performing car under 100k.