This may sound like a dumb question, but how hard is it to determine if a used bike has had gear drive cams or other mods done? I just bought a 2001 Dyna w/29,000 mis. I can see the K & N air cleaner element and the thing seems spot-on as far as throttle response goes. It runs really well. I would swear it is only a hair slower than my '02 Sporty 883/1200 w/SE air, 9.5 to 1 Wisecos, Andrews N2's, and Bassani Pro-Streets. This is my first Twin Cam so I don't have much to base it on. I'm about to spring for head porting and a 95" upgrade. Wouldn't that be embarrassing if it turns out it had already been done....????!!!!