the 00 SI has a B16? You don't need a GSR ecu, that is the most expensive ECU on the market, because it has the IAB control circuitry.
You're probably better off with a P28, and conversion harness, I have a guy that sources these, internally converted just like hondata.

-PHiZ

Do some searches around here and honda-tech, this is not an uncommon problem, see what other solution people have encountered.

Also, you'll have to disable knock sensor in code, for your application.

Just change the byte at 60E7 to 00