You can have up to four remotes coded for your car. If you look on the back of your remote it should have a GM/L #. That number has to match on all the remotes, and I can pretty much guarantee that any 2002 remote won’t be compatible. Also, I have never heard of a GP with individual presets (for seats/mirrors and such) depending on what key/remote you use. I recently set up a spare remote for my car, expect to pay at about $20 bucks for the remote and $50 to have the dealership code it. And yes the dealership has to code it, but who knows they might do it pro gratis. Also be aware that if you buy the remote from a dealer it will cost about $100, I bought mine from Midwest Keyless for much less.