That firewall seems to be a common issue! I haven't had any problems with mine since I patched everything up. I also have never had any flutter issues with mine, although I keep my speeds down by actually using the throttle every once in a while unlike a lot of people I've seen flying these planes! I use single aileron servos on mine. They are Futaba coreless digital 9252's that are putting out around 120 oz-in. or so at a regulated 6V. I use 4-40 connections with ball links to help stiffen things up as well and this combo has been problem and flutter-free so far.