Mufflers
I had a set of the knockoffs and a set of true Flowmaster 40s on my truckj and the knockoffs are a little quieter. 40s are loud. Something you might want to check is how much they weigh. The knockoffs I had (universal sometimes labeled Jones) were heavier than any Flowmasters I've had. If that is a concern for your situation. My knockoffs didn't seem to have as bad a RRRAAAAAPPPPP to them when standing on it as the 40s. With the 40s I could make store windows rattle when I went by. I'm putting Ultra Flos on my new exhaust. I only have so much hearing left to go and it is for Rock n Roll. With Summit you get free shipping and if you haven't ordered for a while, they usually give you $25 off your next purchase on your receipt.