b16a or b16asirII, The b16a in a sol will take you um...1-2 months to wire the thing just to get it to start. The b16aSIRII will take you about a full weekend. The thing with keeping your engine in there now and combineing that d16z6 is that the trannys suck, they are not designed for harsh driving. The b series are performance engines and the d's are for good gas millage.
Reliabilty all depends on how you take car of it, yes the b16 is a good engine but if every day your starting it in freezing temps and then before you get to the end of the street, you hit redline, yea of course the thing is going to give you problems. Both d and B's can last forever if you take care of them, the reason why you rarly hear getting 200k miles out of a B16 is because they are too fun not to accationally beat on them, d series on the other hand, there is not much diffrance from 7k and 3k rpms, it is slow how ever you look at it.