Possible Lipo problem?

I already have an elite 4800 25C 2s lipo, great pack if you ask me, but im also looking at the elite 5000 35C 2s lipo, or maybe even a Neu 5000 25C 2s...

Im also thinking of investing in an eagle tree system, even though i only use my car for drifting, i like to know exactly how the electrics are behaving when being used!