Guess that's on newer models. My 95 will redline in N. Do you feel or see any type of difference after cleaning it. It didnt have many miles on it, you wouldn't see as much difference as doing it on a car with 160+K milkes on it. Did the smoke that came out smell nasty, like carbon burning, or have more of an oil burning smell? I think the seafoam itself will also cause smoke, but you can tell when it's carbon burning.