Going to go pick up a 2015 XL Denali Monday. Dealership mentioned Vehicle just has one key. They wanted to charge $264 for the other key but would "waive" the $110 programming fee. My question is what's preventing me from programming it on my own? It seems the instructions are included in the owners manual but dealers are telling me they have to program it. I found a new key in programmable state with uncut emergency key for $80 on eBay. Can I program it myself and take the key in and have it cut at the dealership/locksmith?