info on Emaxx upgrades...please help

Hi,

I am new to the RC trucks world and have bought an Emaxx. my question is can any body advices or prepare a list of the parts that can be replaced in the Emaxx regarding the drive line, gear, shafts and other things to make the Emax much heavey duty with more tourqe in the 1st gear?!! No crush protection parts are needed and i dont care much about high speed on the 2nd gear as it is fast enough for me.

I would really appreciate any help in this regard as the local RC shop in my city have no upgrades parts at all!!!
I did bought a 7cell batts 4200. other parts are the original manufacture parts that keep breaking after few tuff runs only!!!
Please help me guys and many thanks to all of you.