i was wondering if the prochamber uses the stock cats or do i need to buy new ones with it. And does any 1 know the best place to buy it

 

You can get the one that bolts up (not really some cutting needed) to the stock cats or just go O/R..........O/R is a much better idea because you will actually get a little hp gains from it (theres really no point to buying one and having it catted). Go to MACs website.