Stock. Its great. Its white smoke! I bet if you asked the guy behind me in stop and go traffic while I was in regen yesterday how he liked how much the truck smoked he would have told you it smoked like a bat out of [email protected]((I have the sct custom 325hp tune and when i kick it i can lay out a crap ton of smoke i was just woundering what yall are seeing with yall are seeing with yalls tunes and what yall thinks the smokest tune is???