dive deep ST. Not sure. I think I had it priced out to a minimum of $160 for the intakes. It is fixed now. Anyone can use it on Screamin demon coil pack, mac intakes, and the rear support girdle (the beefy differential cover that sells for $127). This will get the free freight so small items like mag lite clips, VHT nitshades, etc will all be freight free when you order one of the listed products.
Alan- the demon is an aftermarket coil pack. I have had positive reactions on idle and acceleration from a lot of customers. I heard of one dyno run (0 gain) but the plugs weren't gapped (which is specified to get any gains).
I wouldn't call it a major seat of the pants improvement, especially with an otherwise healthy ignition system.
The short story is every ignition missfires, the question is how much. The bigger the gap that fires consistently, the less miss fires you will get. Any HP gain will be translated to extra MPG. Think about it. A miss fire means the gas was burnt in the cat, not for pushing the cylinder. You can see how that would lower HP (you ran on 5 cylinders instead of 6 for that cycle) and you can see how it lowered MPG (that cylinder offered no go to move the truck).