nothing wrong with the 'type' of chassis you have. However, if you look at the cost of really freshening up a car, vs. the cost of a new kit minus what you can sell yours for..... usually better off with a new kit.
Since we'll be seeing you at R/c Excitement soon, bring what you have and we'll see if we can get you running..... get a new belt and some short flush screws..... we'll build when you get there.