I'll second the OS.61FX and in-cowl muffler. Good scale power
but not a rocket. Balance was achieved by moving the Rx pack
3/4 the way back to the tail feathers. As I said before
on the many posts concerning the Lance...I'll sure miss her![]

Another gentleman flies one with an OS .91FS Surpass
and it flies with a little more authority.. I.E. He's able to
fly wider loops , responds better on takeoff and
has better reserve power.

The beauty of the .61 setup is that it is completely enclosed
in the cowl and looks very clean....hope that helps.