Looks like we've switched gears into tune talk. I like it! IMO the factory 4R engine tune and range of self adjusting parameters is VERY good when compared to other trucks. For me it has always adapted quickly to higher performance expectations when fueling with a higher octane. My Silverado was not as snappy, didn't seem to adapt within a reasonable timeframe and couldn't always correct for knock when running a higher octane. A custom tune made the Silverado a performer but that was necessity. I have not experienced that being the case with the 4R because as long as you're selecting 90 octane or above (you desert runners or Rocky Mountain folks may need more) engine management always adapts to perform with ZERO noticeable knock. Right now I prefer not to be locked into using a higher octane like you are with a pre-tuned ECM swap. I'd also like to skip the hassle of loading and reloading tune files that match desired use with a customizable flash setup. For me, it's nice to have the freedom to fuel with the octane I think is best suited to my desired use and let the ECM adapt from there. If I ever do select a tune, I'll pick the one I believe will best manage the areas where the TCM lacks in performance. If a tune provider can show me solid data with improved shift controls especially when towing or expressway driving with the cruise set above 80, take my money!