4S lipos are perfect for starter boxes. I run two turnigy 5000mah 20c on my box, and after a weekend of racing where I ran a buggy and truggy, the voltage is just under 4v for each cell. It also gives the starter box more oomph than the 12v batts.
If it's already set up for 2 stick packs or a 12V battery no need to rewire it.
Jeff
The Warnings & Cautions discussed in this manual cant cover all possible conditions/situations. It must be understood that common sense and caution are factors which cant be built into this product.