....Good, bad, or ugly? Put it in my 98, 195k 4.3 and it has noticeably quieted it @ start up, idle, and the motor is smoother @ idle. Mileage has improved 2 mpg.
I think I've only seen 2 commercials, on it, & been long enough I've forgotten about it. I've seen or heard nothing else on it.
I have nothing to try it on, unless I was looking for mileage improvement. And that's rather hard to verify.