Arkansas

So only 2 cats on a 400? And how will a magnaflow 91000 be on my 400? That link u posted basically just talked about full systems and not cats

Ali SC3

iTrader: (10)

any of them will work you need the correct diameter one for your car, and one that is cali certified if you live there. best way is to measure.
I opted for the shorter magnaflow model (they have different lengths) and I passed smog just fine.

Arkansas

I live in Arkansas just like my name says so im not worried about smog lol. The 91000s have a 2 1/2 inlet and outlet so it should work.