Setup for lipos

[MAXX10]

Hello everyone,
You guys have a very informative forum here.
Right now I have a fairly stock E-maxx, I'm looking for a brushless setup and I was looking at these lipos (http://www.skysharkrc.com/shop/index.php?cat=24&shop=1&) what do you guys think about them? Has anybody ever used them? What about the charger? I would go with (2) FMA scorpions, but I want to go with higher voltage like 22.2 or 29.6 with 2 lipo packs in series.
What are the advantages of running at higher voltage (14.8 vs 22.4)? Efficiency? Runtime? I'm looking for long run-times w/40-50+mph top speed. I am relativly new to this so I hope I'm making sense.