performance chip questions

[Perch43]

all right, i'm clueless at this stuff, i know absolutely nothing about the performance chips. i don't necessarily need the extra power, but looking for some extra fuel mileage - which they all claim. what are some options? est cost? performance/mileage gain? etc. thanks guys, i'm sure you get asked this all the time.

2003 silverado 5.3 Xcab 4x4, z71, tow package, 70,000 miles

i occasionally tow up to 3000lbs, but mainly just no load. and use 4x4 when hunting, driving in winter, etc.

i am having the hard shift issue which seems to be a known issue with these trucks - dealer said its "within limits". and i have read that the perf chips will cure this.

[Perch43]

bump

[SolMan98]

OBDII system do not have "chips". You options are a handheld tuner or have a custom tune performed. Do a search on those items.