how to handle insurance if installing performance modifications?

I called my broker yesterday. Been told that Aviva will cancel my policy if I put a aftermarket exhaust on my motorcycle. On the other hand, the new exhaust will arrive on Friday.
Good thing is, my insurance renewal upcoming next month.
anyone has experience to insurance performance modified motorcycle?

thanks

Cosmetic modifications don't matter much so far as coverage and cost. Performance modifications on the other hand certainly can and you should make your insurance company aware of them - failure to do so could result in your coverage being cancelled if they find out (material misrepresentation), or in the case of a claim, nullified.

So, if your current insurance company has already told you that they won't insure the bike with aftermarket performance upgrades, you'd probably be wise to start shopping around now.