The extra shift puts it in a crappy part of 4th. If it had 4.10s or something to max out 4th that is great, but being at 4k for a few hundred feet just bogs it down in 4th. Now if it was wrapping 4th out, that is fine, the extra shift isn't a deal, but not accelerating for the last 200ft is.
With traction already an issues, 4.10s would make it worse, plus the 3.73s were bad enough for mileage and hooking on the street. The 3.31s are perfect for trapping 117-119mph at the top of 3rd.
Well you know your car better than me as far as it not pulling in fourth when it downshifts. Like I said, a lot depends on your power band, and it's all in the math as to which is ideal. And now that you are discussing other things like mileage and traction, well we weren't factoring that in earlier.
Are you planning to stay at your current power levels? I'm only asking because adding power is going to pretty much going to have the same effect on mileage and traction as putting in lower gears. I see you have a pretty powerful, well, an extremely powerful corvette, how do you keep the wheels planted with that thing?