Major Catastrophe, I agree with Tony C. i.e. you cannot lose with either one. Do not get too excited about performance numbers with regards to rpm unless you know how much time is on the engine. A brand new 2.1 will not run as strongly as a well broken 1.8 but this will definitely change as time accumulates on the 2.1. I have the 2.1 on a 14.5 pound Extra 300. Performance is awesome and gets better with more time, about 50 flights so far. I like the Menz 20x10 prop very well. very quiet and very good vertical,downline braking with very low noise. definitely a good combination.

jmw