Honestly, for the money, I'd go with a Novarossi. They're stupid cheap for superb quality and Novarossi continues to set records in racing. Novarossidirect.com is the place to go. I got a Legend 28-8 for $170 for my LST2 - the Legend 28 is basically an updated 528XR that used to sell for $400 or thereabouts. Picco makes fantastic engines too, but are more expensive.