ok, the B series will ALWAYS have more power than the D's when equally built, and as for the r/s ratio for all motor, when boosted it doesnt change. and the B16 is 1.74, B18C 1.58 and B18b/B20B is 1.54, dont know about the D's.
and the four door doesnt weigh too much more than the coupe, no its not a 4 door thing. if you just wanna drop in and go, get the B18C5 wiht bolt ons and youll probably ghit a low-mid 14 when you drive it to its potential, depending on your altitude, if you wana build it you could boost a B18b for about the same price as a B18C5 and youd beat the mustang.
gotta go, ill answer more later maybe.