it doesnt make sense, you say you want it for drift (small turbo) then you say you want not heaps of power (small turbo) then you say time attack (big turbo) then you say extra power come in handy (big turbo). which one do you want? it would seem odd to fit a T78 to a std engine, you certianly could do it, but why would you bother?
with bog stock everything you would be lucky to tune it at 12psi and not max everything out - aka pointless
wait till the car comes over and then check it out
if its got all the suppporting stuff on it, sell the T78 and get a mid sized hks GT28x/30x series and away you go, even a pair of GT-SS would be fine
but as its already in single mode, its probably cheaper to keep it in single mode