The advance recurve should get you about a 10% improvement in highway gas milage, but that depends on a lot of other factors. Replacing the coil and module helps some. Usually allows you to gap the plugs in the 40-45 range. On the V8 the module upgrade also buys higher rpm, stock limits to around 5,000. Another change that makes an improvement is an MSD-6 box, gives longer spark durattion, also helps smooth out lumpy cams.
BTW - Like Chip, I am not a fan of Mr.Gasket parts. Very low quality from what I have seen.
