I wouldn’t have kept the truck if there weren’t tunes available. I have the gde compliant tune. Helps in every way. I don’t think 6000 pounds is going to be a problem. I tow 4000 all the time and I don’t even know it’s there. Your different tow rate numbers are due to them being equipped...
I installed the compliant gde tune yesterday. On the way back from dinner last night it showed filter 80% full so we popped up on the highway and took it for a drive until the regen was complete. Left this morning and about a mile from the house got a 90% full message. I drove it on the highway...