I hate to be the bearer of bad news, but:

Two 5s packs, while though they will power your truck, if wired in series the cells longetivity is at stake. Though you will have an LVP, what if the voltage per cell within the pack varies? The whole pack becomes usless b/c of one cell. Now if the 5s packs were wired parallel, if one cells charge voltage goes down inproportionate to the others, the other cells will proportionatly charge the cell to nominal level. In a nutshell, to power your sytem you should buy one motor (probably like a 12-14xl...why do you want to run two motors anyway?), one esc, save money (by only buying one system) and then buy--i know this may sound crazy-- two 10s packs and wire them parallel.

This is the only way to make sure your lipo don't undercharge and ruin themselves. An LVP is solving only 25% of your undercharging problems.

This is just an option though, the risk is yours to take.