are you talking about an engine swap or front end? i ask cause a lot of people have done the front end swap. it would also help if you could provide the year/model civic you have.
as for the engine it should be pretty straight forward, although some ppl here have said you need the rear engine mount from the Si.
if you're talking about the front end, i know you need the headlights and bumper at least. dunno what else.
hope this helps some.