Sorry to be the bearer of bad news... Hitec servos are notorious for not centring accurately, and are not used by anyone in pan cars. Yes, you need to have all the steering mechanisms sorted as people are suggesting, and the right servo saver. Nonetheless, even if all this is perfect, the Hitec is likely to let you down.
If you are using most 40Mhz systems, then a Futaba 9602 analogue servo is the best buy. If you are using most 2.4GHz systems, and any with high response functions, then you will use the Futaba 9650 digital servo. These are by far the most popular, and the most reliable. I've used four 9602s in various cars, and currently have three 9650s. They have never failed, and they are valuable second-hand because of that.
If you can re-drill the mounting holes, then a Savox might do, but they are involved in a lot of interference problems with 2.4Ghz systems. There's a good Sanwa equivalent but I can't remember the number. As a straw poll of any pit will tell you, Futaba has the greatest number of drivers, and for good reason! HTH
