Seriously? I've had a power commander on a bike (not anymore, I didn't like the longer start time) and would never have bothered to tell insurance. Aftermarket intake and exhaust too. On a cruiser especially, it's all just cosmetic.
To those being ridiculously honest: Would you tell them if you rejetted too?? You rejet to fix conditions in fuel delivery that aren't optimal, for a million reasons; elevation probably being the most 'legitimate'.
Seriously, is my radio a mod? Clubman bars? Lightening parts? I'm rebuilding a couple CB750's, and I'll build them however I want based on what stock parts I can get ahold of, and when asked, it's as stock as it can be. As stated before, parts wear out, they get replaced with aftermarket parts.