[PaleMelanesian]

If you run all day long at Wide Open Throttle, it might help a tiny bit. In real world driving, it usually doesn't. It might actually hurt engine efficiency. And then there's the temptation to floor it, just to hear that sound.

I wouldn't do it.

I a previous life, I put dual Flowmasters on my Suburban. The started rusting within a year. I live in Texas, where there is no salt on the roads. They're not the best quality. I then moved on to the Cherry Bombs. Sounded amazing. Neither did anything for mileage, though. That's when I traded it in for a Civic.