Yes. It will SMOKE the new stock emaxx.
As far as lipos go. You can go with higher quality packs (enerland) and then you can run smaller capacities cuz they will be capable of putting out the amps that your system will draw. But, the smaller packs will provide shorter run times.
The lower capability packs (TrueRC) require them to be a higher capacity to make them capable of delivering the amp output you want. This will deliver the longer run time and be capable of delivering the current you need. But, the bigger packs weigh more. More weight can cause more strain on the drive train and such.