PhilH said:
I'm guessing that the transmission is available at a discount from some Acura dealers?
Yes. However, if you're not doing it yourself, (a) some dealer service departments will require that you buy the new tranny from them, and (b) those same dealers may give you a nice discount themselves, considering that this is quite a substantial purchase.
Any transmission work is something I would leave to a mechanic with a lot of NSX experience. You're about 100 miles from the top NSX mechanic on the East Coast, Bernie at Davis Acura in Langhorne Pennsylvania (just the other side of Philly), so you might want to consider letting him do it unless there's someone closer that you feel would be experienced at this.
FWIW, I think that some of the other tranny upgrades for the five-speed, such as the short gears and/or the ring and pinion gear - may make more sense than buying a new six-speed.
PhilH said:
I've heard that going from a 5-spd to a 6-spd is worth about 0.2 seconds for 0-60. Does that sound right?
Let's look at the numbers (0-60 and then 1/4 mile) for various swaps (and we'll thank Bob Butler for calculating them):
'91 5-speed stock gears stock R&P 5.31 13.67
'91 5-speed short gears stock R&P 5.09 13.56
'91 5-speed stock gears 4.235 R&P 5.18 13.57
'91 5-speed short gears 4.235 R&P 4.96 13.48
'91 5-speed stock gears 4.55 R&P 4.98 13.43
'91 5-speed short gears 4.55 R&P 4.74 13.38
'91 6-speed stock gears stock R&P 5.09 13.56
'91 6-speed stock gears 4.55 R&P 4.74 13.36
Given that the six-speed is so very much more expensive than simply swapping out some of the gears on the five-speed, and the performance results are similar, you might want to consider doing the gear swap instead.
There are also other mods (headers/exhaust, supercharger, etc) that may give you a bigger performance difference per dollar spent than a gear swap. But the gear swap may give you some additional perceived advantages (reaching redline faster) that don't necessarily translate to faster actual acceleration.
As with most such things, if you can get the chance to drive another car that already has these mods, to see what it's like, it might help you reach your decision.
Your money, your car, your choice...
