ORIGINAL: MTK
I don't know why "everyone has told you" that this engine needs to turn 11k. Why would you want to run a 4 stroke that fast anyway?
A few years ago I used to fly at the Sepulvida Basin in LA, and there were a bunch of guys there who liked to put YS .91's in 40 sized ARF Warbirds and tear up the sky flying in formation like a swarm of locusts. One of these guys told me that YS engines were overrated because he had trouble getting more than 11k on a 12x8.
There's one in every crowd. (Or in this case, about a dozen)