It's not the easiest swap out there, but if you have some mechanical experience it's really not that bad. I found the hardest part to be the wiring, not so much hard as it was just really time consuming. I wanted it to look nice so I opened up the civic harness and hid the new wires. But seeing as you have a Si, that's a few less wires to add then most have to deal with.

Any specific questions?