Just got my first Traxxas and wow... I've already been looking at all the customizations available and I don't know where I want to start. Obviously I will need to upgrade to the Lipo batteries with the parallel or series connector but then where do I go? What are the "must have" upgrades? I saw a roll cage and could see it's practical use but do you guys have any other "must have" upgrades to really get this thing rolling?