Fuegobird

there is no D18a1 but there is a B18a1... see HASport for mounts for the B, and if you meant D15a1, your car already has a better engine and you wouldn't want to go back to a D15a1 from your a3 or a4

research blacktop wiring or obd0 conversion, there should be something in the wiki about it.- this is basically converting the oem Si vacuum advance distributor to the 88-89 integra style (88-91 civic too) obd0, electronic advance distributor wiring... this is a simple conversion, from there you can convert to obd1 if you want but it isn't necessary. You WOULD have to convert to Si wiring since you're starting with a carb'd car.

see my thread in the swaps section, I (with help) outlined how you can run a 'modern' D series engine with the, almost completely, stock harness by using a certain distributor (I have one and probably access to more) and a modified stock carb IM, or better, a stock 88+ dual keihin manifold/carbs setup.