Last september (about 4,000 miles ago) i bought and had my mechanic install the borla exhaust for mopar. I dont remember what the part # was but i looked into it pretty thoroughly and made sure it was ok for my car (an auto) and not the six speed. Lately I notice if im crusing along at a pretty high rate of speed (70-80mph or better) and need to come to an abrupt halt, it seems like the car doesnt downshift correctly. it seems like the rpms get stuck at 2000 or so and dont want to drop below that. It's only for a second or two and then it finally gives and drops down to the next gear. anyone else have this problem with the borla exhaust or any of the aftermarket exhausts, or is there something wrong here?