I have a lmm duramax. I love it I've owned it over a year and never a issue until recently. Bought it with 97k miles abone stock nd it just rolled 130k when the dpf completely plugged. I travel for work with a large fifth wheel. It's got a 6in lift with bigger tires very clean truck. So I knew I needed to get rid of the oem emissions stuff just hadn't got around to it yet. Well it bit me in the *** and put me on the side of the road. I'm an OK mechanic and had tools so I pulled the egr off and cleaned it but not the cooler. Wasn't bad at all. Went and got a scanner. All fingers pointed at my dpf. so since financially I've taken a few hits lately I wasn't prepared for this so to save some money I bought a h&s mini max for 500 bucks and took a Sawzall to my exhaust hacked everything after the cat off. Truck runs great it's loud obviously but runs great. Tuner has stock, 60hp, 120hp and 175hp switchable tunes. I run the eco/tow tune 60hp. Its been like this for two weeks now. Tuner advertises that it disables egr as well. I've been driving it like this for about two weeks. It's got awesome power and I'm getting 23mpg on hwy. Now ive scraped up the money for what I originally wanted which is full egr delete with up pipe, efi live by one of the big names, lift pump, s&b intake, 5in straight pipe, fuel rail plug, edge insight etc etc. But for now she is running 3-4 feet of pipe dumped under the truck. I have been watching the truck like I hawk. Ganges all read normal. I'm always on top of fluids and filters. I use the truck as a truck and do not baby it. I am a lead foot occasionally but don't drag it do donuts or wheel it. So I've noticed that if I get on it it puts out a little bit of Grey smoke I've read it could be because the tune just isn't enough fuel to make it black?? Don't care for the smoke just was worried about the color. I also noticed after acceleration and I let off the peddle it lopes for a second or two at idle rpm but not every time. I have not relearned the transmission yet which I'm gonna do but if I really get on it from 1st to 2nd it has a noticeable pause almost like a defuel but doesn't shift hard. That's happened twice since the current set up It is also downshifting oddly which is why I think its just trying to figure out the new added power. 'm thinking the tuner may just be a pos or I'm just freaking myself out. It runs great regardless just a couple things I noticed. Power is all there and no codes at all.