I have both the Mag .91XLS and the Mag 1.08XL. On a smaller prop the .91 will out turn the 1.08. It has been my experience with 2 1.08s that it is not a good high rpm engine.

I still recommend a 15-8 or 16-6 for it. It needs some big lumber on the front.

The ASP engines, made for the European market, may have a higher compression than the Magnums, made for US use. The higher compression works better with a lower nitro fuel, 0% or 5%. I live in Florida and use 10% all the time with no ill effects.