From my search last fall, there is only one Protuner in Co. Logic Imports and I have heard nothing good at all about them. Mac Autosports in Parker is contemplating becoming a Pro Tuner and periodically has others come in to do Protunes on their dyno. I can't quote who it is off the top of my head but they are well respected. On the western slope you're probably screwed. Given the choice, drive to SLC vs drive to Denver, I'd just go to Cobb. Check out here for more Co specific information.