I intended to spend $100 max on a new motor for my minibike. I ended up spending about $600 for a new motor, torque converter, and components for a full electrical system and full motorcycle lighting. Once I got started I kept thinking about how sweet it would be if it had this, then that, then the other thing. I'm finally pretty much done spending money on it, just hammering out the couple "rough edges" it still has when I have time.
I'm sure it can be done, but international vehicle buying has loads of red tape and taxes/fees that have to be sorted out. I've heard from several people it's a huge hassle, but if you're willing to do it can save you thousands.