Have run the 5.5 motors in both mine & my sons cars recently & have same problem, got drag brake set to max & brakes to max but nowhere near as good as a brushed motor.Find that you just carry a lot more speed through the corners now which is good for my son as he can cope with it but i just crash more often!!
. Changing to LRP system in the near future & hope for more success. Dont get me wrong the novak systems are superb but brake capacity not on a par with brushed set up we use in 4wd.