I'm flying my SE ARF with a TT 46 heli engine and a standard OS muffler and it balances fine at the recommended CG. I shoved the barttery as far forward as possible under the fuel tank. I didn't find the need to add any sort of nose weight on mine.

Performance on the recommended CG is perfect. No bad tendencies what-so-ever.

(I have a pic or two of it in my gallery here on RCU)

hth

Jeff