[Rare Iron]

With the minimal amount of exhaust system assy. on these cars, if you are going to achieve quiet, you are going to lose major HP. There are 2 effective ways to quiet down relatively short sidepipes: 1. Squeeze the flowpath diameter so small that flow is significantly reduced, & add soft packing material to absorb flow (current stock systems - 1-7/8" +- flowpath approx.). 2. Use a non straight-through muffler core inside the muffler cavity. Walker used to build a muffler that looked like a glasspack externally, yet had two (very small dia.) staggered flow tubes internally. These were called "Royal Scots." Flow on them? Terrible. Noise reduction? Yes.

Now, if you want sound attenuation qualities + good flow, you'll need at least a 2.5" (OD) flowpath & soft packing to absorb. If you are over 480 flywheel HP, run a 3" (OD) core muffler with soft packing. I believe this will give you the best of both worlds - as good as can be hoped for. Run as long of a muffler as you can fit - shorten the collector & shorten the exit spout.

There's no sense spending THOUSANDS of dollars on a high HP motor only to have your mufflers rob you of 100+ HP (not to mention torque) in the power band.

-The Powerstick/Cobrapack blacksmith.