[mhoffman]

Not exactly what you wre looking for either, but I put an SW chip and M&K muffler at the same time (just the muffler, no cat-bypass) and noticed an appreciable difference in throttle response thoughout rpm range. I cannot attest to any specific hp change, but it is much smoother. Steve asks specifics about your car, gas, exhaust, etc in order to dial in the chip to your circumstance (you can read more at his website)- seems a better approach to matching your car's fuel/air/ignitiion system to what you have than to what the manufacturer determined 20 odd years ago. The muffler made the car sound like a completely different vehicle. I read where some of the earlier M&K mufflers were loud, but mine is very pleasant and non-offensive.

Both suppliers are great to work with and supply a great product and great service.

My two cents.