I always wanted to do this to one of my 160fx's and compare the performance to my Evo 26. It looks like you are getting nearly 1000 rpm more out of the OS! The 8700 rpm quoted by Horizon for the Evo is with a tuned pipe and low load Mejzlik 18X6. The glow 160FX spins that prop at 10,000 rpm.

My concerns for long term use would be the wrist pin seizing in the piston and faster wear on the crankpin and con rod. But then again gas has better lubricity than methanol so maybe the reduced oil won't hurt anything. You could add a couple oz of castor per gallon for additional protection or run Pennziol at 8:1 vs. 10:1.

Too bad nobody makes a sheilded McDaniel Style twist lock plug cap for the ignitions. Installing a cm-6 plug will change the chamber volume and lower compression.