long story short. can i drop and go with the wiring harness that came with 94 civic Ex. with auto trannsmission, if replaced with jdm d15b vtec. and what parts can be interchanged to gain peak performance. and where to locate replacement parts and what motor size to ask for. i read on some sites that jdm motors are hard to find parts for. but others say that a usdm d16z6 will work. didnt realize original post was so long. thanks for the help. so if i am swapping usdm d16 with jdm d15 vtec, it is more or less plug and play. auto tranny to auto tranny. already set up for vtec? sorry if i am dumb, but then again it isnt a mustang.dying to try it.