Nismo sports catalyzer or weldina exhaust?
 

Dunno which to get first. What do you guys think? I believe each would give equally slight gains, but the jdm weldina costs 1k more than the high flow cats. Then again, there may be legal implications for the high flow cat's. Bottom line is that I would like to get the setup that's less loud than the other. Any feedback would be appreciated. Thanks.

You gotta be pretty darn stupid to pay, or even consider paying, what is it, 1900, for Nismo's high-flow cats, L-M-A-O

and for exhaust, bassani > jdm crap

The cats are 1300--exhaust is all preference--But maybe I should have asked a more general question: high flow cats or 3 piece exhaust first? Which would be louder and which would cause more A/F problems?

depends on if you like the stock note or note - cats will deepend and louden it. exhaust will change it completely.