Yep, what Mark said. If you're one of those people who can't resist firing it up at home to annoy the neighbors, scare the dog, wow your buddies, or just for a good nose hit to pacify you till the weekend, you might consider power valves. The plugs will stay a lot cleaner under those conditions. Jet down about 6 steps when installing the pv. As far as any performace advantage, zip, zero, nada......