Dan;
The Norvel's are all superb, GMS work fine just like an OS, Haven't heard anything about the Megatech but the numbers look good.
All of the Magnum engines I've owned have run very well at approx the same Rpm's as a OS. I have Old brand new Veco's and Enya's Mark IV's still in the boxes I'm setting up for a couple simple series ME109's. I think will be fun but fragile aircraft compared to true Coroplast combats. $100 thats a tad expensive for Combat, you really don't need something that expensive to beat around.