Doing bit of reading about the Cayman GT4, and how crazy high it's gearing is. Looked at the 370Z max speeds in gears, and even that is getting some high speeds at the top of 3rd for example.
Comparing VQ37 redline vs the VR30DDTT redline, believe it's 7500rpm vs the 7000rpm, we could hopefully guess top speeds in 3rd.
I believe 370Z is capable of 95mph, so that leaves the new Z at 89mph, if all else remains the same.
For me that is high, but lot better than the 370Z and miles ahead of crazy Cayman GT4 gearing.
I would personally prefer top of 3rd to be no more than 85mph (136kmh) to allow us more shifting gears haha.
