Wait, you cleared a P0420 code just to pass smog? That's wild, man. That code is for the catalytic converter, it doesn't just go away for good. The cheap reader cleared the light, sure, but the underlying problem is still there. I'd be shocked if that car passes the actual emissions test, the numbers don't lie. That's a temporary fix at best.

My sister got one of those devices and said the same thing. She was shocked how much plumper her skin looked after a few months, not just tighter.

Read a great article about designing for the guy who has to build it. They called it "shop floor reality." Makes you focus on what actually matters.