All Ruckus riders, Just some info?

I've been riding for a while, I own a 2004 600 rr. Had it since zero miles but the ruckus scooter seem like fun and would definitely like to own one just for the custom looks and different things I seen about them on youtube. lately they've been popping up here and there, so the question is: What's the year preferably I would want and what about the engine? I keep seeing GY6 but don't know crap about it. I'm a mechanic by trade and a fabricator on the side so I was thinking to get me one to trick it all out. I'm in southern cal (Rialto CA) if anyone has meets or very good info. Thanks