depends on your funds..

if u go with a b-series swap u'r gonna need a different turbo mani & a bunch of extra stuff..

B's & D's are bout the same price anymore, not really any price difference, just the additional crap u'r gonna need like ECU / Mounts / Ect. that will add up a bit.

personally if u'r looking for mild power above stock (200-250hp reliably) i'd just stick with the D & make it manual.

Best of luck to ya.

Tony