tbh if your gonna spend some money on batteries go lipo even tho they sound like more of a hassel then Ni-Mh packs they actually much better.

Your more likely to have problems with the nimh packs down the road getting outa balance,dead cells and the lipos are much better suited for a large heavy truck like the E revo.
Not to mention much lighter which is something the E benefits from greatly

I speak from experience on the fact NiMh packs are just not suitable for a vehicle the size of the revo if you actually want to enjoy running your truck