new 05 V6 with dual exhaust?

I have some questions about dealer options on the V6. My brother just bought one, and it has a hood scoop, ground effects, tinted windows, and dual exhaust. Does anyone have any information on this, or did the dealer just customize an ordinary V6? It sounds good; not as good as his wrecked GT (SLP Loudmouth II), but good. How much horsepower would the dual exhaust add?

Yeah, I guess, but for what he paid he could have bought a GT and had some change. Anyways, it looks and sounds good, so I guess he's happy; I'll post some pics if I can (he drives a truck, so is usually not at home).