I had basically the same experience with my JBA 3" single, you do lose some how end torque, mpg remained the same for me, its been on the truck for 4 months and has got a lot of rust on the mounts, pretty much have to get it welded together otherwise you'll keep having to re-clamp the pipes together. My drone went away after i got the 305's put on though, which i found odd. Truck has a nice sound but i wouldn't buy it again. :beatsme:I ordered a JBA 3 inch mandrel bent stainless single outlet catback for my 5.7, and had terrible drone issues at about 60-70 mph. Also saw a noticable decrease in fuel mileage, and low end power. I took it back off and am running the stock exhaust now, but I wish I had some sound sometimes. But that would be the only reason for the system, which makes it hard to justify financially. If I was going to spend the money on it, it would have to be the Corsa, because it is the best sounding one that I have heard, and is supposed to have no interior drone, but I have no idea what it would do to mileage or low end torque because it is a very similar design to the JBA system.