Currently I am running test pipes on my STS rear mount turbo. I can't stand the smell and will be installing HFC. I was thinking about replacing the resonator on the stock exhaust midpipe with 1 or 2 of these vibrant 200 cell HFC: http://vibrantperformance.com/catalo...roducts_id=855.

What are the downsides of doing this besides some power loss? Will the HFC work in reducing the smells being placed further downstream? Will 1 be sufficient or should I go with 2?

 

Stock exhaust is a little bigger than 2.25" at that point, I thought. The main thing about placing the cat that far back is it will take longer to heat up. Once it's heated up, yes, it will cut down on the smell.

 

also , If you replace the resonator with a Cat , you will likely get rasp and a somewhat crappy sounding exhaust note.

It would be better , given room, to place the new CAT(s) inline before the Resonator(s).

A single Cat in-line should be adequate to knock smell down.

I run two 100 CELs in "parallel" , just before the rear diff and they work pretty well.
Two 100s in parallel only reduce my peak rwhp by ~10rwhp out of 520.