Originally Posted by '10Anamoly

This is true for the math, but the exhaust temps should be pretty similar despite outside temperatures. Perhaps a bit cooler in the winter but still pretty close. The side branch resonators cover about 15 points of frequency completely and then begin to lose a bit of efficiency. On my car it knocked out all the drone from 2200rpms through 3000rpms. I expect in winter for the car to make a bit more noise but probably not much. Can always report back when its cold outside.