Well I went to my LHS with the fuse and cowling to see how the MVVS 26 would fit in. They only had one muffler and it would not even come close to working in the Stearman. Here in Germany the MVVS engines are a lot less expensive than I can find them online, even after you convert dollars to Euros (which is very sad right now). I decided to wait and see what muffler would work and there aren't many available for that engine. After crunching many numbers thrust vs wieght and cost. I reverted back to the idea of a glow engine. I think this kit is right on the verge of Gas and Glow and for the weight you get more power with glow. I am planning on putting the Saito FA 180 in my Stearman and make my next plane bigger and go Gas then. The Saito weighs less than the OS 120 and has more power. How can I go wrong with that. The only down side I hear about the 180 over the 150 is that it has more vibration. I don't know how big of a deal that is. can anyone tell me? The 180 is only $20.00 more than the 150 at wholesaletrains.com so it only makes sense to me to go with the 180 since it doesn't weigh any more. Of course I am still looking for advice on this decision.