Any b-series trans will work, of course the short ratio ones are more favorable. I had a b20 with both a cable GSR and an LS trans. Nice thing about the b20 is it makes a decent amount of torque(for a b series) and is fun to drive in a lightweight chassis. I have bought two b20s from tigerjapanese, one was clean a f**k and the other not so much. You never hear anything bad about hmotosonline. Remeber there are three b20s, the b20b (low compression p75 head) b20z (higher compression p75 head) and the other b20z (compression slightly less than b20z but with p8r head). The third one is the most favorable.