I have cored cans that were shortened. I honestly wish they weren't shortened because the sound is a little harsher and UNGODLY freaking loud. Loudest damn bike at the track every time. Doesn't bother me so much but I get hazed about it a bunch. My incentive to get aftermarket pipes would be to get a deeper exhaust note and to drop some weight. Even the cored stock cans weigh at least 10lbs more than most anything out there that's aftermarket. I love this bike but she's a tad hefty. I am slowly working on trimming some of that mass off. New cans and an ultralight battery are high on the list.