Hi Ray, I bought a Sr. Telemaster to mount my G20EI on, and I am looking forward to doing this project and flying. The fuselage width at the firewall is 4.5 inches which is plenty wide for the G20EI. I am glad someone else is going to do the same thing. I plan on starting my modifications next week. I will have to transfer the radio gear from one of my other planes to fly though, but it should be worth it. I am not certain what all I should beefup besides the firewall, I have heard the fuse may twist a bit but I don't know if this is true for the ARF, the kit, or both. Good luck with your build.
Thanks...Brian