I'm not sure about the servos you mentioned, but...
After my Genesis LE steering and throttle servos failed (one electrically, one mechanically), I swapped them out for Hitec 5645 digital servos. The difference in steering is amazing. They are fast, smooth, and powerful. I read that they consume more power, but I haven't had any problems with a 1200 mah receiver pack and several tanks of driving on one charge (I gave up before the batteries did). The servos were good to go, drop-in replacement, with no external programming. For one or both servos, I think I had to reverse them via the transmitter. I used plastic arms on both servos.