Some people say that the turbo trannies or the pull style trannies are stronger than the push style trannie, but ive heard that no one can really tell the diffrence on the duribility, they break at about the same whp with about the same bause also so i really wouldent be that picky. Really there havent been that many improvements to the strengh of the 5spd, the only improvements have been in the syncros, but the trannie was kind of strenthoned in 98? when subaru added 2 more boltn holes to reduce tranie flex, but since the SVX cant use those bolt holes i dotn think they have really been improved. The only 5spd trannie that has been improved in duribility has been the brand new 05 legacy turbo trannie becasue it got a griddle to reduce tranie flex even more. Of cources the STi 5spd will be stronger becasue they got the better gear sets but thats about it.
Personlay i used a 90 or 91 legacy trannie, with the 4.11 rear end, i havent broke it yet and have been fairly abusive. But i have only put about 4000 miles on the swap so iam not sure how long it will last yet. All i know is that my syncros are horrible i need to doubble clutch upshifting or down shifting into 3 so it wont grind and now iam just double clutching pretty much most of the time. Im not really sure how many miles are on it, the odometer said the car had 230,000 miles but the trannie had 124K written on the side of it and the car had a fairly new clutch when i took it out.
ALso the best trannie fluid has not been synthetic for me its been the vavoline 80/90 GL5 rated with some molybdenum mixxd in ive tried a couple of diffrent fluid combos and this works the best by far. I dont have to double clutch all the time now.
