Depends on the person running their mouth. My mustang...I couldn't really lie about that horrific screaming sound from the Procharger. So I told them I had a broken A/C clutch. lol Some people bought it.

The only thing I would be sneaky about is spray...cus that's pretty much all you can lie about, and how much boost you're actually running. Most car people can hear/see what has been done.

-Ant.