2008 Sierra 2500HD Duramax Four door 6 1/2 box, full egr delete, airdog, CATarpillar fuel filtration system upgrade, 4.5 downpipe with 5 straight pipe exhaust, five different towing tunes wEFI live, new thermostat, 256,000 miles, new batteries a year ago heat blows hot no smoke fulsynthetic change and wix filter every 3000 miles religious for as long as Ive owned it, access tonnoue cover. If you dont hear back from me at my number please bisman message or email and I will get back to you immediately thank you