Cheaper than a new head unit and all the associated stuff needed to keep OnStar, chimes, factory amp, steering controls etc. working.....
Yes.
It is completely plug and play.
Toughest part was finding a place to tuck the additional bulk of wires to get the head unit back in.
It works through the XM source, so you select XM1 as the source then press SEEK UP and it scrolls through XM, AUX1 and AUX2.