The secondary O2 won't throw the ECU into limp mode? My friend had a '97 (or '98, I forget) ITR and he put a test pipe on and got the CEL. Everytime you were around his car you could smell fuel and it seems sluggish. He ended up getting a custom testpipe made with a welded on pipe the O2 sensor screwed into. It wasn't actually in the exhuast flow but strapped to the pipe and thermal wrapped to keep it up to temp and the CEL went away. His car run 13.9 with just an I/H/E and some good driving. He's running a Hondata system with a turbo now.