01 accord 2.3 ulev Catalytic Converter
 

Need to replace the cat, did research, some people say the ulev has a special cat, but every site i look at doesnt specify base/lev/ulev/sulev as different. hoping somebody may know if there all interchangable or if i do need a specific one?

18160-PAA-L21 is the part# for ULEV catalytic converter
18160-PAA-305 is the part# for non-ULEV cat
18160-PAA-L40 for the SULEV ("may be discontinued")
(I only looked up for 4-door cars)

What I don't know is what the actual difference is, or whether they are mechanically interchangeable.

someone was also telling me theres some tricks to tricking the cat, something about park plug spacers between the o2 sensors and the exhaust?

Maybe, but I suspect the PCM on the ULEV car is a lot more capable of detecting those kinds of tricks.

put the spacers in, it seems to have worked, 400 miles and no CEL yet. stayed away long enough to pass emissions on the inspection, im happy :D