My bad, i didnt realize that this was a nitro kit at first. I would either use two of the servos in the first link or Id use the second servo for steering and the first one for throttle/brake.
I would ditch the 4AAs and buy 5cell NiMH packs.
Good Plan!
Not sure what your budget is but Id look at one of these two if it were me.
Savox SB2271SG - High Voltage Brushless Digital Servo .065/277 @ 7.4V
Savox SB2291SG - Monster High Speed Brushless Servo, Black Edition 0.042sec / 347oz @ 8.4V
If you're just looking for a decent budget radio Id get a Flysky GT3b. If you're going to be racing then Id get a middle of the road radio from either Sanwa or Futaba. Whatever you're budget will allow for. As for servos Id look at Savox servos. The faster and the more torque the better. Let me...