I used the hitec HS645mg(approx. $30) for the brakes and throttle great torque for the brakes. The hitec HS5955MG(approx. $109) 333oz of torque and has been proven to wrok well for the steering.

There is always the dual steering mod too. Works very well, the parts are about $30 including second OEM servo. And the OEM servos are about $15 on the 'Bay to replace one. I use this mod and have had very good luck. In fact look for my detailed write-up on this mod, this weekend.