You want the 7950 on steering FOR SURE! There's no other servo to run. The 7940 barely holds up on steering in a buggy, it certainly isn't a good fit for the truggy. Throttle is a bit tougher to choose. I've been running the 7940 with great results, but to tell you the truth, if I were to do it now that the 7945 is out, I'd probably go that route. The 7940 is certainly adequate for throttle, but the more torque you have, the more reliable it will be with less chance of a servo failure. I really don't think you need a servo faster than the 7945.