hey dude, if your lucky you wont throw the cell for it. I DONT HAVE CEL, and I drove like 20 000 kms witout egr...
as far as the bolt, I used the old bolt and got another "standard bolt" to fill the inside with the head from the outside and welded those 2 togheter.
perfect tread with a new head to tighten it.
it look gettho but its the only way I found to have a perfect bypass (I bought like so many fitting that where all off treaded...
before I tought about this one)