this is the good old arguement, youll probably get 50/50 for longer or shorter. IMO and thats only MO, that longer gears would only be good in that you will have more time for revving out after you get traction. personally i have the LS trans (no turbo) and its beat as all hell, and wouldnt want it even with turbo. but at the same time if i had an si trans (cause i had and SI and know how short the gears go) i wouldnt want that either because you would just be spinning and sure that would be fun to show off in, but not very useful when racing or just driving quick. so as for b series at least hands down id say gsr trans for turbo, i dont know much about d series trans, i guess the s20 (or whatever it is, ex/si trans) would prob be the better of the bunch