Battery setup

[jim Ball]

Hi Everyone, I am fairly new to the rc boat scene. Been running a geico24 in standard form for a while and just now got an impulse 31 v2. Little question I take it from the general blogs around that without upgrading the terminals etc and the fact that Proboat have changed their battery requirements that its best to run only 4 s and not 6s. Onto my main question, the wiring is setup for (2) 2s in series making 4s. Is it worthwhile changing this to parallel and running (2)4s would there be any reduction in amps available. Also if parallel is a possibility could I safely run (2) 5s in parallel on stock components. What is the general feeling on Turnigy nanotech batteries. One question turned into a few sorry about that. Any help appreciated.