Hey David
I've got a Aviastar .46 that Sig sells. I thought that I would give it try since I haven't heard too much negative except for a bad carb seal, but that would mess with any engine. I can get a Macs header that fits and run a pipe on it, should be interesting. I've never run retracts so I like the simplicity of the E-flight and if they fail from no fault of mine I won't install them on a glow engine again. I cut the tristock off the cowl area and I'm now in the process of fitting and gluing formers.
Thanks for your help.
Dave