Hi all: I had an in-person Black Bear tune in Concord, NC this weekend, and wanted to share my experience. My truck is a 2012 Yukon Denali AWD with 100k miles on it. I elected not to purchase an AutoCal with my tune, reasoning that I had no need to return it to stock (no warranty), and no real plans to modify the engine any time soon. My overall experience: I met with Justin. He was right on time, having spotted my truck before I could text him to let him know I was there. We spent the first 10 minutes discussing what I wanted: disable the AFM, improve shifting and disable the downstream O2 sensors. He suggested that he could also disable the speed limiter. It wasn't on my list, but I figured why not? During this discussion, he did the programming changes, prompting me to turn the ignition key to run and back as needed. When that was done, he told me to start it for a road test. We went on an urban street loop and an interstate loop, transitioning through various driving scenarios from stop-and-go to WOT freeway blasts. He pointed out differences I would see in the performance of the truck. And he did some live monitoring of things like misfires and O2 sensor performance (more below). The whole thing took just under 45 minutes. AFM delete and fuel economy: This one is easy enough to confirm. I kept an eye on the instant fuel economy and driving mode all the way home (1-1/2 hour drive). As expected, it stayed in V8 mode the whole time. Whereas I could see 93mpg at times with AFM on, the best I saw was 53mpg with it off. However, these instant readings were for a few seconds at a time, at best. I typically only see this when coasting downhill. For 95+ percent of the time, it's in V8 mode anyway, with the hilly terrain in my area. So I don't expect any significant drop in mileage. Whatever I do see will be worth it for valvetrain longevity. Transmission performance: For me, the results are mixed. I'll start by saying that I think the ideal automatic transmission would be telepathic, by which I mean that it would understand my intentions and shift accordingly. Since we can't have that, I was hoping for shift programming that would do a better job of accommodating my driving style. To a large degree this did happen. The shift points seem to work out better, resulting in fewer times where the transmission was in the wrong gear for what I wanted to do with the truck. There is one particularly challenging part of my daily drive where I slow down to 5mph at the bottom of a hill, take a sharp turn, and accelerate back up another steep hill. This frequently causes a harsh, late shift just after the turn. After the tune, this happens less frequently. But it still happens about 1/3 of the time. I suppose this is unavoidable, though my other trucks (older, and "dumber") don't do it at all. In addition to changing the shifting behavior, the speed and firmness of shift has been noticeably improved. In normal street driving, the shifts are detectable now, but not noticeable unless you're paying attention to it. Under full throttle, the shifts are significantly faster and firmer; bordering on harsh. I'm okay with this, now that I've driven it for a day. But it took some getting used to. I would say, it certainly is fun! On a smooth, dry road my truck feels much faster than before. I think a large part of this is due to the rapid shifts. On wet pavement, I'm pretty sure the full-throttle shifting would trigger traction control. I don't think that's a bad thing. But it's something to be prepared for. Just to summarize, the transmission performance is better than before. It still doesn't quite meet my expectations. But BB has to work with what GM allows. In the vast majority of driving scenarios, it is much better. And in a few scenarios, it's about the same, maybe slightly worse due to the faster, firmer shifting. Engine performance: Justin and I didn't discuss it. But the BB website talks about horsepower increase. Justin did say I should stick to 93 octane, which I already planned on. Clearly, the factory tune will likely be more conservative. So I'm sure there are a few more horsepower than before. But I couldn't really tell in normal driving. Under full throttle, it feels noticeably faster. But I think this is more due to the shifting improvements than actual horsepower increase. This doesn't bother me. From a philosophical perspective, I satisfied my need for more power by buying the 6.2L engine in the first place. If I ever want more, I still have options. And future re-tunes are free! Downstream O2s: Not much to say here. I have no plans to remove the cats any time soon. But now if they get plugged, I don't have to replace them. I can just get a replacement "off-road" Y-pipe. Keep in mind SC has no inspections or emissions monitoring. So this is a no-brainer. Live performance monitoring: In my opinion, this is an undersold feature of the live tune. Justin could watch for misfires and monitor things like O2 sensor response to gauge the health of the engine. This was important for me because I just bought this truck with 99k miles on it. So I don't know the history of its maintenance. In my case, he was able to detect a very minor random misfire, which he attributed to likely carbon buildup. In addition to the fuel cleaner, and AFM clean I already did, his advice was to "drive aggressively" for a while. Okay. No problem, lol. Had the misfire been localized to one cylinder, it might have indicated a plug, wire or coil going bad. He also monitored the O2 sensors, which by now are probably about due for replacement. He confirmed that they weren't tracking together exactly right, and opined that they are probably original. So now I know to replace them soon. Beyond those things, he didn't see anything else wrong. So there is some peace of mind in that knowledge. Summary: Did I get my money's worth? Absolutely. Would I do it again? Without hesitation. Justin was great to work with. He was very knowledgeable. My truck drives better. And I have significantly more peace of mind about its condition. Lastly, if I need to make changes down the road, I can either ship my ECU for a re-tune, go back to Concord for a re-tune, or buy an AutoCal and download tunes. Plus...sticker! Thank you Justin, and Black Bear Performance!