Ummm.... Don't get a b16a2 & don't get a hydro tranny. If you go b16a2 you need to convert all the way to OBD II - that's not fun. On top of that, there are no motor mount kits on the market currently for a hydro tranny b series motor into a ED/EF Civic.
Plus, the only major difference other than the OBD generation is the compression ratio - 10.2 for the 1st gen vs. 10.4 for the new Si's. You can easily do better than that by investing the $2000 you'll save over the motor price & having a **very** custom tranny mount setup done on CTR pistons, exhaust, intake, CTR intake cam, ITR exhaust cam, fuel pressure regulator, cam gears & put the $100 or so you should have left over towards a Hondata.
just my 2 cents...
Eric