I picked up an ´07 FLSTC a month ago. One of my complaints was that it didn´t sound like a Harley. Of a bigger concern for me was the whine from 5th gear. I called Harley Customer Support, who put me in touch with an engineer. After explaining the reason for the whine (use of spur gears for 1st and 5th), he went on to discuss the use of new Screaming Eagles slip-ons. Essentially, he stated that the decibel level for the Screaming Eagles (made after April, ´07) was the same as the stock pipes. Unless your changing for asthetic reasons, forget it.