Just shock! I had 7499 mufflers installed on my Elantra, and they had no tips for a month or 2. Under light acceleration, I would experience ear thumping drone. But now, with these tips, got'em from AUXITO and welded on at a local shop for $20/side, the drone is gone! In general, there is way less noise inside the car, but I think outside it is about the same. I doubt this has anything to do with the resonation, and more with the extended length out the back so the sound doesn't bounce around in the rear bumper. They are heavy, quality metal tips, fit my Elantra perfectly.