with the rustler i used to run (rustler xl5 with a 3300kv brushless motor/70a esc), i really didnt find a whole lot to really improve the steering. i did find around 35wt oil in the rear and 40wt in the front got it handling a "little" better. I'm sure you could get some small diameter music wire and bend up a sway bar for your rear. never got around to trying that though. unsure in the grand scheme of things how much or if at all would improve the handling. really would depend on what surfaces you are running it on.