i was looking around and i noticed a lot of guys on youtube and on here have thrush welded mufflers. i like the sound of them, so i was wondering what kinda of mileage increase did you see when you put these on (right now i get about 18 city/highway and 21.5ish on all highway) and if there was any drone in the 1800-2500 rpm range.

 

You may or may not see a difference. Don't get excited about it, though.