40 la would fly it but you won't be happy with it. The kadet will take a anything you throw at it. I've seen a guy put a saito 1.5. He reinforced the heck out of it of course, he was towing 1/3 and 1/2 scale glider with it.

I put an OS 91 on mine, took all the dihedral out with floats and was allot of fun, sold it awhile ago and is still flying. As a trainer it will do just fine with the tt 46