I concur, the "rolling coal" thing is something I've never agreed with. Just had an idiot last week think it'd be funny to give a blast of black smoke to a group of motorcycles approaching from the opposite lane.
On other forums I've read where delete kits are getting hard to come by as the feds are cracking down on the manufacturers and sellers.
It's true that in NYS any emissions equipment that was present on the vehicle at it's manufacture date is supposed to be in place at inspection time and vehicles are indeed plugged into the OBD port at inspection time. But there is an exemption I think if the vehicle is beyond a certain age, possibly 20 years old. I don't know if these guys are loading the factory tune back into the trucks before inspection or how they get around it. I'd think the factory tune is going to set off a check engine light if equipment is missing. A CEL is generally going to flunk inspection.
Any modifications done to the only diesel that I've ever owned (a Ford 7.3) made it a little more efficient and blow LESS black smoke if anything.
Rest assured that if one of these jackholes did it to the group of bikes we ride with... he would soon be sucking on his own tail pipe ..