Well with the cat back section of the exhaust off, I was able to stay 1 car length back from a LS1 Z28 through second and belive it or not I had him out of the hole (he must not have known the lights like me) anyway with the exhaust back on which I did before I left the shop today, It seems useless just more stress, but it still works perfectly. If you can for a day or two take the cat back section off and let her rip