Ok I am preparing to get everything ready for my 3 spd auto to 5 speed manual tranny swap. I am debating using the 12A tranny over the 13B tranny due to the more aggressive gearing. I have both. The car will be used every other Sunday for Autocrossing, and probably twice a week to and from work. I really want it to preform on the track well opposed to getting good gas miliage or top end. Of course the trip to the track is 50 miles round trip all on the Interstate. Anyways what do you guys think? Also I fi have read correctly the 5 speed should share the smae mount as the 3 speed auto as far as mounting correct? I know with the 4 speed auto you have to fab up a mount.. But i think this is a direct bolt in.. Thanks for any help you have. And if you post an answer please post your resoning.. thx.

 

The gear ratios are quite similar except for 5th gear. Check out this link.

http://members.ij.net/mrmazda/tranchrt.txt

I'd use the one that makes the least noise . If you don't have a limited slip diff rear end, get one as well. You'll get rear discs and taller tail gears (4.08 vs 3.90)in addition to the LSD.

 

Use the -SE tranny. It will get you better gas mileage on the highway, and you won't be using 5th gear for AutoXing anyway.