Dirty, I have not used A123 batteries and honestly was expecting the voltage drop to be on par with Nickel Metals. Perhaps I will give them a consideration. I still think that long leads can be an issue. Yes it does depend on what RF is floating around in the enviroment and at what power level. When I was more competitive in IMAC I would attend 3 to 4 contests in Las Vegas. Both at the Bennet field and North Vegas. That region has a reputation for a very high noise floor. There are several military installations in the area and we can only guess what they were transmitting. At that time I was equipping my 40% models with a Smart Fly Power Expander and Turbo Reg. Yes regulators do burn capacity and I do recomend to guys adding regulators to up the battery capacity at least 20% The airplane had 13 JR 8411 servos and yes Ihave flown a sequence that had a double positive snap roll in the center of a long downline. All 13 servos are loaded in this case and the airplane is traveling approx 60 mph. JR would never admit it but being the first really high powered FET sevos available for airplanes, they were qutie noisey. Current draw had to be pretty high. With this setup I never had issues in what I would call a dirty enviroment. Obviously there is no real wrong answers with this stuff as there are many variables. For me what is safest is to err on the overkill side and fly with 100% confidence and concentrate on flying and not if the airplane is going to continue to listen or not. Funny you mention RADAR, I am a little aware of what that can do as I currently work on the E2D program.