I have the 28% Extra, and I must say, this one will more than likely be your "daily driver"! I am sure it has something to do with my setup\ C/G, but the only thing that I can come up with bad, is that there is some coupling in KE. I can "fly" the coupling out, so it's not that bad. other than that,(THE ONLY LITTLE THING!) what a plane!!!!
I also have the 3MM 53, and have had pretty darn good luck with it. I have heard pro's and con's about this engine, but I am on the "pro's" side of the fence....The engine is broken in now, and running like a striped *****ed ape, so I decided to prop it up a bit- I did however find out when it will stop pulling with a 23B vess... 6450 on the ground with a bunch of pull, but just never wound out in the air like the 23A or a 22/8 bunny prop. 22/8 btw if I remember correctly was right around 68/6900 on the ground. I'm running 50/1 semi synthetic (dont hang me here guys) golden spectro and 91 octane in this engine @sea level, and it just runs sweet!
Also, if you are interested, I am running 5955tg on the rudder(1) and 5985mg's all around elsewhere. choke is now manual, and throttle is just an 821 std dig. I also went a bit heavier with 2 batts/switches, but peace of mind for me and spektrum- the Tanic pack a123's from tom- GREAT BATTS! In a great flying plane! You'll love it!