Stick with the traxxas widemaxx arms, not RPM. Full RPM wear plates and bulkhead brace. From their just go with all UE drivetrain.You will want new shocks, UE , RPM or big bore traxxas. I am going to link the UE stuff from their sight. When it is time to order give your list to mike and he will hook you up.
Drive train:
HArdened steel Idler
titanium center drive shafts for E maxx with cups
Ultralite 8 spyder Diff kit
6mm steel cvd with dace 23mm hubs set of four
Steering:
UE Servo Saver
Hitec 5955 steering servo
Add brushless of choice: 9920 will keep you from having to upgrade if you decide to make a switch. BK wanderer 7xl, or 9l, will perform very nicely on 12-14 cells.
do not forget your:
Tony's screw's
Have a nice day:cool