I have my 2011 duramax, 60K miles in the second time in a month for the cleaning exhaust filter message coming on and not going out. First time they said it needed a manual regen. Cost me $300. Don't ...
I did the delete on my 09 and couldn't be happier. Cost wasn't bad and only took a few hours to do my self. Worst part was fishing the wire for my tuner (efi live with dsp5 switch) through the firewall. My lmm is different than your lml and there is a ton to read about doing the delete. I usually drive with the 90 hp tune and have about 25,000 miles on the delete with no problems, smoke or exhaust smell.