Its been a long time since my 300ZXTT was stock, but I think the 370Z would definitely take it stock. Not so much once even a few mods are done. I doubt my 05 350Z would have beaten a stock 300ZXTT though.
The biggest thing to me about the 300ZXTT is it has a different feel from all the other Z cars I have owned (82 280ZX, 86 300ZX, 05 350Z & 09 370Z) in all of those cars you knew you were driving a Z just from the familiar look/feel of them all. the three guages on the center dash being a small example of that. the engine noise, the shifters, etc. The 300ZXTT is unique in its driving experience among Z's IMO.
I have had my 300ZXTT for about 13 years now, and its still my favorite Z. Its a blast to drive, fast as hell and just wants to go. The 370Z is a close second to me, better than all the others I have owned. The quality of the build of the 300ZXTT is a big plus for a car you may want to hang onto indefinitely. Every little thing still works in a 1991 car.
it is a great, unique Z in the lineup of great Z cars.