Tim,
I am flying my Kangke Laser with a BME 50. I had to remove the metal flying wires and move the rudder servo up close to the CG to get the plane to balance. The rudder servo is suppose to mount in the rear. I moved it inside the fuselage just behind the receiver tray to balance without added weight. I could have added a pound of weight to the firewall and been done with it but I wanted to keep the weight down. I also replaced the stock steel flying wires with light weight cables. In the end is came out perfect with no added weight.

So if you want to buy the lightest, most powerful engine you can find be ready to make some changes. Unless you don't mind adding firewall weight.

By the way the BME is a fine engine to consider. I don't know what my all up weight is on the plane, but I am sure it is lighter than most with the modifications and no added weight. Regardless the BME is more than enough for 3D and multiple up-line snaps.

My engine is still on the first gallon and slightly rich but is spinning a Menz 21x8 @ 7300 rpm.

Tim