I am so disgusted with American Muscle, I have spent in the last 2months with them $6000 + I bought a tuner and since day 1 have had a spark knock, I have called them over & over trying to get resolved and everytime it is still same issue. The refuse to give me a refund!!! I have done everything they requested from the copper core plugs, to the pcv valve, to the pcv fillter to getting mass air cleaned & even had the carbon treatment done to the engine and still a spark knock. After as much money as I have spent with them as a coursesty you would think they would give me a refund seeing that everything they wanted me do I have done and it is still crap! You would think that if you have a customer that has spent what I have they would make me happy give me a refund and keep me happy! Instead I have a crap tuner that is useless to me!