Quietest Catted X/H-pipe for Whipple'd GT?

[Paul.]

I recently installed a 2.9L Whipple on my 100% stock 2011 GT. The car made 591 rwhp on 91 octane with the Whipple tune. Every time I mash the throttle, I can smell the factory cats burning and I'm starting to fear for their safety... especially with the 1/2 mile races coming up soon.

The problem is, I'm grumpy as hell and want my car to be as close to factory-quiet as possible. I hate noise. Let me reiterate. I HATE NOISE.

What's the best catted mid-pipe that will keep the noise down as much as possible? I will continue to use factory mufflers since they're super-quiet and I don't think I'd pick up much/any power from switching mufflers.

Paul.

 

[LTD5.0]

I would look at the Magnaflow Xpipes. They have one with high flow cats for off road only and the other is 49 state legal which I assume would be quieter but I don't know how it would hold up to boost. I haven't used them but have seen them and they are a quality piece. I have read that their Xpipe design is not as raspy as others.

 

[TSHOES]

Even if you change to High flow Cats you will have a very noticeable difference in exhaust volume. From my understanding on boosted cars with stock cats, they need to come off ASAP.

 

[hand-filer]

Still running factory cats and after 3 years no issues. I don't do prolonged high speed runs so that might factor in to their longevity.