Your post says 12.8, I didn't watch the full video, so that Flex in the video is the new guy on the list - Jason Allen, right?
BTW, that video is kind of dismissive of my work IMHO.
My 12.52 was with no meth, stock turbos, stock downpipes on 75 shot.
My 12.4 with upgraded turbos, upgraded fuel system, downpipes and cutout
My 12.3 was same mods as 12.4 + 75 shot of nitrous
The 12.52 to 12.4 was a TON of work and effort. I never ran the 600WHP setup unfortunately, trans wouldn't let it happen.
Also those were HIGH DA runs, over 4K for each one, that's why I asked what yours was, corrected times will show even more of a delta if you ran at sea level.