Getting a used programmer

[yukonxl1500]

I friend at works brother just got rid of his 03 Tahoe and has a programmer from Hypertech and a larger front break kit for sale. Can I use his programer on my Yukon..same engine or is the programmer married up to his vin.OBD and therefore useless on my Yukon.

I am also thinking about installing headers and highflow cat, some say to remap with a programmer and others say the onboard computer will automatically adjust. T or F ?

If T, is there a special programmer for such a task or who would I take it to.

Thanks