I'm going to chime in here for a second.Ispyral,there actually is a B16A1 in Europe the 90-91 B16A1's had a numerical designation at the end of the block code.And I believe it was the CR-X the very first JDM rex w/the B16A also had a A1 at the end,but it is very rare to find,or maybe the teg Xsi,I forget which one.But I know there is one.
And to Bambbrose,there is no O in hydraulic.And for your car I would definitely not bother with a siR short or long block you'd be screwing yourself out of 10hp and getting a older block.Look for a B16A3 from a delsol vtec (going to be really hard to find) or a B16A2 from a 99-00 si as suggested above.