Brand, I am a new guy too.....I have quickly learned that batteries are your best investment. I had a cheap set and upgraded to IB3800 and the difference is amazing. When you buy, assembling yourself is the best way to go. I would recommend using all deans products (wires and connectors). I didn't believe the connector made that much of a difference, but when I put the on the stock E-Maxx, there was a noticable increase of power. Invest in a nice soldering iron - atleast 60 watts. If you have a cheap set of batteries, practice putting those together. A battery jig would be nice, i have been looking for one of these, but it seems everyone is sold out! Take a look at:
www.balakracing.com
He has an awesome step by step directions for assembling batteries.
If you get pre-assembled batteries, it seems most folks on the forum recommend side by side set up and not the stick packs.
Mike (the owner of this site) has really good stuff with great prices along with unmatched service.