Speed Limiter
Change the top speed that the vehicle will reach before the engine automatically limits the power needed to go faster.
Tire Size
Correct the speedometer if you have changed your tire size from stock.
KAM Reset
KAM stands for Keep Alive Memory and is where all the learned adjustments that the computer has made over time. Most of these are settings for fuel trims and information to help with idle stability. You would want to reset the KAM after fixing a mechanical issue like an air leak or a bad tank of gas.
Crank Relearn
A crank relearn is a process that the PCM goes through to recalibrate its knowledge of the relationship between the crankshaft and camshaft.