No one in any official capacity is going to tell you it's OK, because no one wants the liability that comes along with that in case something does go wrong.
I built a tube door for the driver side of my XJ years ago. I brought it with me to the Winslow inspection station, and the guys there thought it was neat. They said they probably wouldn't pass it though, under a blanket 'unapproved equipment' or something like that, because while they can approve aftermarket suspension components & steering as it relates to the lift laws, alterations to other parts of the vehicle don't fall within their purvue.
I got a ticket for the same tube door - it was written when I wasn't in the truck, and left under my windshield wiper. The offense was 'unsafe vehicle - no driver door'. I also got a ticket for no inspection (sticker was expired).
I went to court with a bunch of pictures of the tube door installed, along with some printouts of the federal side-impact crash test standards giving dimensions of the test rig, where & how it impacts the vehicle, what the vehicle is expected to handle, etc. I showed all this to the prosecutor and they dropped the ticket as long as I paid the one for the expired inspection that day.
They did
not drop the ticket based on the merits of my case - honestly I really had no case, I just went in there with a bunch of information to wade through in the hopes that it would confuse the process enough to make them drop it. Anyone who's ever been to traffic court in NJ knows that you can get things dropped/reduced for no reason other than expediency. However, I carried the ticket around in my glove box just in case, and the one other time I did get pulled over for the tube door, I showed it to the officer and said "I got this ticket in Aberdeen for the door, and it got dismissed in court." Still earned me a mudflap ticket though.
Not saying that everyone's experience will turn out this way...just giving another perspective.
