On the torque, do the math for the tires you plan to get. With the help of Pegasus's gear ratio calculater and some torque formulas Jack has posted on older threads on the same topic, you can use that to help figure out how much you are actually losing. If you are only going up a size or two like I did, that quantity of lost torque is not something you really worry about.
If you only go up a few sizes like I did then the power loss is not as much as you'd think. Yeah there is a SLIGHT decrease and your stop and go traffic mpgs MIGHT take a hit, but you are also upgrading for looks and you pay to play no matter the game. My stop and go city mileage didn't really go down (from 13-14ish), my 45-65 mph mileage went up some (17-21 to 18-23) and my 75-95 mph highway mileage went down a bit but I dont have numbers there because I'm not usually on the highway for more than 20 miles. These all have to do with my driving style though. I plan ahead so I'm never in a hurry.
Depending on the engine I can vouch for the gotts mod. I (independently) calculated
up to 9 hp based on quarter mile time comparisons and MAF sensor gains on my 4.6L. I'm also using a drop in K&N filter. Funny thing is that K&N says I should get about 9 with their intake. If you have your doubts test it yourself.
If you want a good idea of your real horsepower without a dyno, go to a local drag strip. Make a few runs that are really close to each other and then weigh your truck. There are tons of formulas that will give you a general number including the one in the pegasus program.
The avg economy on any programmer has a tendency to read high or low. It is one of those things that makes perfect sense on paper but the real world makes it lose accuracy. I'd expect the same effect of the mileage on the truck readout. Similar formula but with different computations.
The vacuum guage is an old school mechanical device that tells you how LITTLE throttle you are using. It hooks up to a vacuum line after the throttle plate and reads the amount of intake manifold vacuum pressure. I think most of the ones you buy in the U.S. and such are measured in "Inches of Hg (mercury)", the original standard in vacuum operated devices. It does not tell you your mpgs but the philosophy is make as much vacuum as you can. The more vacuum means less air is getting past the throttle plate and into the engine...Less throttle = more vacuum = less air to the engine = less fuel usage = better mpgs. You could possibly put estimated mpg readings on it but it will be a multi tier field like on cheap volt meters. Then you'd be spending more time figuring out which number is applicable rather than looking at the road so I don't recommend it.
