From the insurance standpoint, if you make any major engine modifications(swap outs, engine booring, nos, turbo etc) and you don't advise the insurance company two things could happen in the event of a claim. First, they could pay the claim but deduct the difference from the premium you paid vs. the premium you would have paid had you reported the changes. They could charge you for the difference from the beginning of the policy term regardless of when you actually made the change which could wipe out the claim entirely and actually cost you a few bucks. The second option is to deny the claim, cancel your policy(possibly back to its start) and potentially charge you with insurance fraud. That would not only cause your rates to increase due to whatever accident but could also destroy your probability of getting good(everything is relative) rates for your home, auto or bike insurance. The flip side of all this is that if you do tell an insurance company that you made the modifications they could cancel you anyway because they don't want the risk(liability) of a modified bike.
P.S. The adjuster will figure it out fairly easily if they come from one of the big boy insurance companies like Progressive. Most companies have specialized adjusters for things like motorcycles, rv's and boats. In a lot of cases, those adjusters are also enthusiasts.