Buying a bike with a scratched off vin# and no title?

Im looking to pull the trigger on a bike just for the track, and came across a stock 05 zx6r 636. Not having a title doesn't really bother me but the seller told me the vin# on the frame was scratched off by a previous owner. The bike has been sitting in his garage for about 4 years and he has pictures of the bike from 2014 to prove it. It has a dead battery but it starts up with the jump and the engine seems to run fine. Its gonna need new tires and probably full fluid changes but he is giving it to me for extremely cheap. I confronted him about the scratched vin and hes telling me that he bought it like that and that one of the previous owners most likely did an insurance scam with the bike and thats why its like that. Its hard to knock it down for the price hes giving it for and I plan on using it only at the track. Is there anything I should be worried about?Edit: the bike has no track mods at all. The guy said he used to ride it around campus 4 years ago but its been sitting in his parents garage ever since he graduated. via /r/Trackdays https://www.reddit.com/r/Trackdays/comments/d9s2dl/buying_a_bike_with_a_scratched_off_vin_and_no/?utm_source=ifttt