Custom Gear Ratios

[jp]

I know from reading elsewhere that the final drive ratio for the S14 & S15 boxes are the same, but I was wondering would it be possible to take the gears 1-5 from a 14 box, put them into a 15 box, & modify the 6th gear to such a ratio that you could quite happily sit at 1800 or 2000rpm at 120km/h & cruise along saving a good bit of fuel on long distances?

 

[Nicely]

Why the heck would you want to do that? You'd be losing the whole point of the 6MT: short ratios and better engine control.

The two boxes are different sizes, so I don't know how easily that could be done...

 

[jp]

Because I like how my car drives now, where the power is etc & want better cruising mileage from my E85 cause that's half the driving I do in the S14a. There was the possibility of me getting a free 6-speed there about 2 months ago but yer man left it in the mechanic's & it went walkies.