Ive been reading and looking on the web for a couple days now and theres just a few things I wanted to clear up before I do a ZC DOHC swap to my 89 crx si: 1. Does a lighter flywheel make a noticable differerence? I was thinking of getting one to put in during the swap. Also, as far as the whole clutch and flywheel combo sounds confusing. Alot of sites say "upgrade" for 89 clutch? Is it something about the 200mm vs. 212mm size? I plan on keeping my Si tranny and will most likely put in a new clutch atleast. 2. Should I just get OBD0? Is there any reason to get OBD1 instead? 3. Can I use the chikara header I already have? I read I may need to grind out si header port material to line up with the ZC though? 4. Is there any other things I should do during the swap that may be good to do before putting it all back together? Thanks all.