I know a lot of people say don't ever buy the first year of a new engine and they're probably correct.
However, If I was in your position, there's no way I'd pay all that money for the 6.2 when the 6.6 is right there. Not to mention that new interior looks great, and hopefully the seats are truly improved. If I didn't have all the money (and sweet equity) dumped into my stereo and new shocks over the last year, I'd be trading up 100% for that 6.6. But if the 6.6 wasn't there, and a 6.2 with all its known problems was available, I'd 100% get the 6.2 (again).
You have to determine your appetite for risk.