I think either the Novarossi/Top/Rex/Crono/JP P5/B5 is a solid decision. Very reliable, durable and long lasting. The Lamberto COllari B3 and B7 are also great motors for the money- but there durability and longevity still have yet to be seen. BUT, from what I hear from other racers that have quite a few gallons through them they are great engines that put out alot of performance regardless of the price.