I've noticed 2 (perhaps technically 1) bug involving the jet skis in Ray's shop:
1) The cameras don't recognize removal of parts from the jet skis as theft. Gib does, but as soon as he's out of sight you're free to take any of the parts out of any of the jet skis. Other actions such as attempting to enter/hotwire the jet skis, the cameras behave as intended.
2) Ray adjusts his sale prices for jet skis that have had their parts stripped/replaced. Probably not a bug given that when you sell a jet ski to Ray, the price adjusts accordingly to the prices of parts inside the jet ski.
Apropos of nothing, in my game Ray is possessed of a bunch of fancy but non-functional skis, and I have gotten over my buyer's regret of getting the Devastator and replacing it with an unusually cheap and part-less Glow that I proceeded to stuff with high-quality parts that I got for free.
Jokes aside, I've had the game since before release and I'm glad to have bought it and seen how far its gotten since then, I'm on the verge of my first thorough and successful play-through. Keep up the good work!