I have one but have only run it in on the bench. Norvel (NV, short for Northern Velocity) has been around for quite a few years and were made by Russian aerospace engineers, kind of like if NASA ever made model engines
. The engines are brilliant with technology way better than normal (ceramic liner). That said, I haven't heard of anyone using them for CL stunt (possibly because they're not too common) but going by the timing figures for mine I wouldn't expect a 4-2-4 run from it so would most likely need to be run in a rich 2 stroke. Nothing wrong with that either.
Given that the Legacy 40 is apparently designed for 35-46 size engines, others that may give a more stunt like run would be the Brodak B40 (very light but probably not an excess of power), the OS LA46 which a lot of guys have had good success with, Enya 40XZS PRO, Enya SS45/50, ST G51 (you have to fit a much lighter muffler but oh wow, does it have some grunt
). Going by price and availability probably the choice would be the LA 46 although personally I'd have an Enya.