Here in about 2 weeks im adding a K/N FIPK to my 5.3. I already have dual 40 flowmasters with turndowns vertically in the fenderwell. Now,
im also thinking of going with a programmer, most likely the hypertech III. Does anyone currently use one, do they work well? Are they reliable?
Does it really cut down on gas mileage or does the mileage stay about the same? Oh, and what about this transmission firmness thing??? I do not have a shift kit. Does a firmer shift actually prolong the life of the tranny????
thanks,
jerry

P.S. : after i install FIPK i will have a nearly new "AIRHOG" filter that i dont need. I have a 99 silverado, 5.3... If anyone wants this filter email me (jerry_smith_@hotmail.com) or PM and i'll let it go VERY CHEAP (seriously i JUST bought the filter about a month ago)

Alrighty, lets see here. You want a programmer? I have a 99 Z71 w/5.3 and the K&N system also. I bought a Hypertech III programmer when I first bought the truck. I had it for a year and a half and at the beginning, liked it. Then my valves began to rattle and the engine pinged like crazy!! I dunno why, but if I un-installed the program, it went away. I eventually sold the programmer b/c all I was using it for at the time was to reset my speedo for larger tires. I purchased a custom tune from Allen Nelson @ Nelson Performance. Im gonna tell you man, it has been worth EVERY penny. It completely blows any hand-held programmer away.

As for the shift-firmness, it will make your trans shifts a little firmer, but I only noticed it under wide-open-throttle. As a matter of fact, thats really the only place the Hypertech works is when your wide open. The Nelson tune works throughout the whole powerband. I've heard firmer shifts (as long as not too firm) will prolong the tranny life.
The mileage with the Hypertech stayed about the same most of the time. And with nelson's tune, I gained a few MPG.

If I left anything out, or you need further info, feel free to ask.