The only thing I would change is the motor and esc. Get a cheap sensored set up 17.5 and the right tires for your track and that car should be gold in a rookie/ novice class. I don't think you need to make a B4.x turn any better than it already does. You could always pick up a set of shocks used at some point but you should be able get that car close right now. One thing you could do so you are not double buying springs, buy traxxas slash spring cups and retainers, 2 sets like 3 bucks each and the you will be able to run the AE big bore springs and those are noticably smoother then the old style colored springs.