You will need to get it done with HP Tuners or EFI Live. Since you are doing that may as well get them to tune it too. Check out Jeremy at Lime-swap.com or her on the form. Also James supermodulation will also tune it too. There are a numbers of other that may tune it depending on where you live.
Your PCM can be reprogrammed with a GM Tech-2 or MDI using the AC-Delco TIS2WEB site for different tire sizes but you have to call the tech hotline with your tire diameter and download a specific calibration file.