|I had heard LOJ was working on an adaptor plate to mount the T56 / 6060 Magnum six speed to the VG motors. Also a company called Granas was on here a while back saying they had done some work on this as well. As I recall, their pricing wasn't very clear, and its not posted on their website.
Although if someone simply wanted to reduce highway rpms, IMO changing the diff ratio would be easier and more practical than changing transmissions. Especially if the engine power and torque has been increased.
First gear of the Nissan 5spd on a 400+ hp TT is really pretty useless with a 3.69 diff. But using something like a 3.34 or even a 3.54 there's still plenty of off the line torque to get things moving, and a sizable reduction in RPMs at the other end cruising the Interstate.
1st - 3.214
2nd - 1.925
3rd - 1.302
4th - 1.000
5th - .752
T56 wide ratio double OD
There is nothing like a wide ratio T56 double overdrive with a 0.56 six gear to calm down the motor at 75 plus mph. I've got nearly 400 ftlbs and could easily get by with four properly spaced gears. Likewise I think a mildly built VG motor could be equally comfortable with the spacing of the Nissan gearbox using a slightly taller ratio in the rear.