Buyer Beware
I act as an Airworthiness Review Signatory, and I have seen aircraft that have changed hands, presumably through "friends" where the new owner has had his toys taken away because there were un-approved modifications fitted to the aircraft. The equipment did not have the necessary release paperwork and the new owner is faced with a bill to certify the installation, have the installation removed or be grounded. Would you buy a car without a full search? Obviously the answer is no, so why do people do it with aircraft?
PM for additional pointers from an airworthiness and maintenance standpoint, particularly if you go the non-permit route.
Happy flying!
Doing whats needed