Does running without catalytic converter(s) or an extended catalytic converter (if this will cause a CEL?) hurt mpg and/or performance of the B18/B20 with an OBD1 TCM/TCU (Integra)? I'll be swapping to a B20 with an aftermarket header soon but I'm just trying to figure out which one to buy. Emissions test is no issue here (funny though I had a Mustang with gutted cats that passed Colorado emissions with no issue)

 

No CEL for OBD1 without cats