Capt Steve:
Update on my previous comment:
do NOT take a "chip" for a whirl unless it really is a piggyback chip that plugs into the port of the ECU board.
F150online.com had a few threads about SLR chips. It seems that this is a resistor, not a computer chip. The resistor attaches to the intake air temperature sensor to 'fool' the ECU into thinking that the air is colder and timing can be advanced.
Bottom line: do not invest in the SLR "chip".
The Big D:
Capt Steve's 2006 F-150 is out of the 3-year warranty period now so it is 'safe' to modify the vehicle at will.
Chris