Nothing, install and go. The VIN can't be changed and the mileage on the dash is stored in the cluster.
The only thing that could keep it from working is the factory alarm. Do you have the factory alarm? If not and your buddy did, it your D won't run after installing it. If you have the alarm and he didn't, or both vehicles didn't have it, you'll be fine.
Lucky you on finding one, I'm still looking. I know SCT is a better alternative now. Back when I got my PCM, it was the only game before B&G and others came around. I'd be happy to get back where I was.