9xl, 5s, Quark 125b + Lipo battery holders?

[MTBikerTim]

So I am planning on converting my savage to brushless. I have to ask just to make sure though. I have read a lot of the threads on this forum and have come to the conclusion this would be a reasonable combo 9xl, 5s, Quark 125b. Would this setup stay at a reasonable temp with the right pinion in a savage? Mine will have the 3 speed in it as I don't really have the kit to make a slipperential. Also for battery mounting I was looking a getting a 3s and a 2s 8000mah lipo in series and mounting one on each side of the truck. I was looking at serums revo conversion and wondering if anyone knows where to get cf U section or if it even exists. CF U section would make really cool battery holders I would think.