you can swap the digital DIC in, however it is MUCH more complicated then just unplugging and plugging back in. heres what you need to do...
1997-2003 Grand Prix Analog to Digital DIC Conversion - Automotive Forums .com Car Chat


as for the heated seats, if your car doesnt have switches for them, it doesnt have the wiring. ALL of that will need to be swapped

as for the power seat.... good luck finding one that has the controls on the left side...