greetings ffr2608 as others have said on pointers for your pershing build is to get the upgrades now as you build the dean ultra plug for battery is the way to go also need to get is bearing kit for road wheels ect. and contact tom w/ www.tomsrctanks.com he has some good upgrades for gun elevation replacement gears and turret rotation replacement gears and will have other parts ect. as for the idler upgrade i could not find a happy medium the tracks was to loose or to tight but with the upgrade it was easy to adjust the tracks better.depending what type of controller and reciever you get and how big of battery you use especialy the reciever as said the lower hull is very small so size of battery will come into affect (my reason for cutting speaker box in half.) where you can put it. and where you can mount on/off switch i choose to mount the reciever on/off switch in the commanders coupla (just an option if not using battle system).the other difficult thing is to get all of your wiring harnesses together either with small plastic ties or tape up real good as not to snag on anythig inside whil turret is moving and try to follow wiring diagram somewhat? if possible and remember to buy some thread lock compond tamiya is very bad to use(messsssy). a thought for metal tracks? and be careful with tail and head lights fragile will break easy. good luck on your pershing build DAN