If you are getting a new engine the OS la series is very reliable BUT low on power, The FX is a great one but pricey. Take a look at the Magnum engines, They have great power and run great and if you ever have a problem the customer service is the best The 46 would be better but the 40 is on sale right now
http://www.hobbypeople.net/gallery/210756.asp http://www.hobbypeople.net/gallery/210750.asp
Dauntae