If you fly most of the time in high altitudes the higher compression
pistons will give you better performance. I am in the same boat here
in Jackson Hole Wy. My toy is sittin in the hangar at 6450 msl and I
always fly in the 11,000+ range. The only hiccup to higher comp
pistons is if you were to relocate down to sea level, then the motor
will be under some higher stresses, IMO the motor should live to TBO
though...

Ben
www.haaspowerair.com

Thanks Kyle and Ben. Kyle, an important point is the altitude where I
fly which Ben's point covers. Last night I read a Sky Ranch article
and the stresses of a 10:1 piston may be problematic at sea level.
But I am rarely at an altitude and power seting where I even get 75%
power. So if that reduces the stresses from a 10:1 (or 9.5 to 1)
piston compared to sea level then it may be ok.

Obviously I am still trying to make a well informed decision.

Ron Lee