robearralliart

iTrader: (1)

I am in California.

Can I run the Stage 2, with full cat-back exhaust, but no high-flow cat?
Stock Intake, filter, etc.

Any problems, re-purcussions?

RideSober

iTrader: (3)

No, you can not. Some seem to think they have done so with good results, but will realize they are mistaken when and if they actually compare their results. I have reviewed the results from a number who have tried, and those that have actually compared their actual Stage 2 performance results with their performance results from Stage 1 are always worse than just running stage 1.

AP Stage 2 is designed to work with a full 3" turbo back exhaust (check the Cobb documentation, it is pretty clear on this), with the stock cat in the way of the exhaust flow, there will be too much restriction.

Just as FYI I ran the Stage 2 MAP for a while making 20 pounds boost, with my turbo back exhaust and thought it performed OK. I would suspect you can probably run the Stage 2 MAP while still using your stock downpipe just fine as the DP is not bad, but that stock CAT has got to go.

Good luck.