For the R154 you need a 1jz bellhousing for it to bolt up, the w58 is a lot weaker than the r154 so i would suggest against using the w58 with a 2jz or a 1jz if you are going to upgrade it past bpu. Good luck finding a 6 speed and getting it to work, a few people have done it, and it takes a lot of time and money to get in, and you have to modify the car car a tranny(specifically the shifter) a little to get it to fit, then you will need a new driveshaft. So basically its alot of work.