motor
Personally, I'm not a fan of rebuild unless you have the tools to put new bearings in it too. Nothing like dumping a bunch of money and then have the bearings leak and screw up the tune.
For the money, I'd look at the stock O.S. V-spec. You can use coupons and get a pretty nice deal at some of the online shops. If you can't go that route, I've seen the Jammin motors and they are fast, but not sure about durability or tunability.
Another thing to consider if your current motor is in good shape and you can wait a little bit is the new O'Donnell Motor. They will be out sometime this season, and will retail for about 229.00.
Hope this helps
Jason