if u did exhaust, intake, jet high flow sensor, with unichip tuned for these mods, u might notice better throttle response, but its comes with spending big $, & i bet u end up removing the unichip like i did. & as far as i know, there are no headers made for the v8, if u did all these things, u might get that 12 hp that u stated, but certainly not with just the 1 , in fact, with just the exhaust & intake upgrade, u will notice the difference at highway speeds, but it will seem to lose some low end grunt around town, u can get that back though by modding the aftermarket intake to be a true cai. but the stock box already is, just remove the carbon filter, the combo of these mods look & sound cool, but they just arent gonna give u the hp ur looking for.