Ok. Yes I'd use it in SF. I'm only a stock whore because I play in CAL and TWL so it's bad practice.
To say the G36E isn't overpowered is just ignorant though. Name a single weakness the gun has. It's more accurate than any other gun, less recoil than any other gun, less base deviation than any other gun, and the highest damage per second of any gun in any mod for BF2. It IS overpowered.
My personal opinion though, a lot of the SF unlocks do a better job of matching up to it than the normal bf2 unlocks/stocks, so it's not that big of a deal. Besides, you get one next round anyway so why cry about it during the game right? The ONLY issue I have is when people use the SF unlocks, particularly the G36E in Regular BF2. I think it was a stupid idea to do that in the first place since now they're basically forcing your typical noob to pay for an expansion just so he/she can compete. (I'm not including the good players who deal with it and kill the G36E anyway, I'm just talking about your normal novice player who can't handle the guns yet.)