I have the 2.5" TTI X-pipe system and the Dynomax welded ultra-flos in the short case on my car, with straight cut tips that exit and inch past the bumper and it's pretty quiet in the car. Rolling on the freeway at 70 (3000 rpm), I can hear the tire noise (and they aren't loud tires) over the exhaust. Other than pretty much right at 2000 rpm, they are pretty quiet. Not bad at all for mufflers you can see through.