I'm with Dave, the TT42GP is a great-value engine that just eats the OS40LA for breakfast.

I've got one that's been doing a *lot* of hard work on our club trainer. It's been lawn-darted more often than I can remember, even onto tarmac. It's missing several head-fins and I've had to put a remote needle-valve on it to save on repairs (after each crash) but it's still an incredibly strong motor.

The 46-sized engine of choice at our club is the TT46Pro. Slowly all the old OS-fans have come around and now every new .46 engine is a TT. They are just so foolproof and offer about 200% better value than OS.