So, I'm not anywhere near as experienced as others on this forum as Wild One, Dilligaf and others, but I've customized the hell out of my truck including a supercharger, stroked and forged, and pretty much upgraded or swapped out every damn system besides the trans.
I have talked to Jay a few times, and while I personally like him because he's a crazy Texan, he's gone a bit off the deep end. I honestly think he's a victim of his own success, he didn't want to scale his operation and took on too much business. I've had tunes by Flyin Ryan, and Hemifever also. They're all decent, but are also very much tuning by grabbing what they have that's close in their library and sort of sending out a 'mass produced' tune with minor tweaks. Unfortunately, while you are still getting a really good tune, especially to protect your transmission, if you do a LOT of mods/customizations like I have, they never quite dial it in.
I switched to HP Tunes from Diablo, and used my Diablo unlocked PCM when I got the I3 on my 2018 and didn't have any problems. I *think* the HP tunes setup procedure backed up and factory reset the PCM when it started, but my memory of it is fuzzy since it took me a while to get HP tunes and the credits all loaded up correctly. I'm not sure if there's a time frame where they changed that, just stating how it worked for me. I read through various forums and found more folks saying it would work than not, so I tried it knowing that it risked bricking the expensive unlocked PCM. I got tired of the less granular tunes and not having more precise fuel maps, and there was a much broader tuner community out there for HP Tunes. I struggled for over six months to find someone who could dial in my tune at WOT! Flyin Ryan is good, but sloppy I think, and spent most of the time railing on me for not going with his cam. Hemifever is awesome, but I think more suited to a more generic customer. Jay I got tired of, and he was sick, and the turnaround time was really long...
I got really lucky and found a guy in St. Louis where I did a dyno/tune session, and it made all the difference in the world. So, just my input for those struggling to find a good tuner, it's tough but worth it in the end.