Originally Posted by maalox
That may not be the exhaust. I had a noise coming from under the car at that speed as well, which the dealer diagnosed as a loose exhaust heat shield. I haven't heard a thing since that was corrected. My car is stock, but it's possible one of the shields on yours came loose during the exhaust install. Just something to check.
When I was under the car, I checked every sheild, and even gave the one near the rear A frame(?) a little taper because it was extra long and straight vertical.
anyways, not likely, they all seemed properly fastened and tight.
Originally Posted by asting
What part sticks out the most? Perhaps a skid plate/valence would help.
Do you know of one that is available to bolt on?
I will say after reading a bit of aero-modding material, that gap between the rear bumper and the rear axle is very large air pocket now that the muffler is gone. Nothing is there to sort of steer the air under that lip of plastic that is the "bumper" that could be causing an eddie at high speeds....