I just got a used seadoo and I need an engine for it. Basically I am trying to peice together a machine from a bunch of parts I have. I need an engine for my GTX and I know a guy on Kijiji that will sell me one out of an SPX. He claims that they are the same. How can I tell? I also want to make sure his engine is not stolen because it is not in the machine still and only sitting in his garage. Is there a VIN number on the engine that I can write down and have checked by police?? I just dont want to buy a stolen engine and then my son gets caught with it when he goes out riding. Thanks for help here guys. I am just trying to piece together a machine for my son so we can go out together, but I'm not very educated on these things.