I think you'd also have to change out the stock servo for avc right? because the stock servo is not digital? Please correct me if I am wrongI've beaten this to death around here, but something like Spektrum's dx4c and one of their AVC (active vehicle control) receivers is a pretty amazing setup. Illegal to race with but that is not something I ever plan to do. The radio is nice too but the AVC is what has really rocked my rcing world.
Google it, the system does everything they claim and it is so seamless at times you forget all it's doing, that is until you turn it off anyways. I can't vouch for how worthwhile it is on a 4wd vehicle, but I consider it literally priceless on my 2wd and overpowered granite blx. As long as the front tires are on the ground it goes exactly where you tell it. No more back end coming around with too much throttle and it tracks dead straight with no steering input regardless of what you are going over.