^^^^^^
Not meaning to start an arguement...
Optimal wheel base depends on what kind of racing the car is used for; a shorter wheel base would be better for autox and small courses, where as the 2+2 would probably be better for larger, higher speed courses.
wheel bases:
2 seater: 96.5 in.
2+2: 101.2 in.
^(I really doubt 5in. makes that much difference for general driving purposes)
As far as curb weights go, the tt's are a bit heavier (due to turbo's, hicas) at about 3500 lbs.
Nissan 300ZX (Z32) Performance Statistics
Regardless, a car can still handle well despite extra weight (new GT-R for example, 3800 lbs.?). That being said, less weight is usually better.
In the end, it all comes down to which one fits you better as far as performance needs go or which one looks better to you. Personally, Function > Form.