I had a Tower 46 in my modified Balsanova 40 and while the plane weighed under 5 lbs the performance was not good enough. I bought a MDS 68 and while it was nearly a half pound more it turned the plane into a really stout performer. It's a great plane and with enough power I liked it even more. I just wish that I wouldn't have lightened the stab as much as I did. Opps ouch bye bye nice plane. I have another one half built and I'm planning on learning from my mistake. :stupid: