What is the problem with drilling some holes? I have the Webra 52 and bought the 60 size Weston Muffler from Heliproz. I used one of the existing holes and drilled one new one with my cordless drill. Took me about one minute to do and the thing fits great and works great. According to Weston they have a 40-50 size pipe #vpgh.40 or the high nitro version #vpghn.40. Then there is a 50-60 size this is the one I used actually for the OS 60 configuration #vpgh.60 or for high nitro vpghn.60. The webra engine has the same mounting configuration as the OS 50 which is a little narrower than the 60. Anyway it is the same muffler just takes one new hole and you are done. Not too hard really!
Life is hard! It is even harder for stupid people!