I probably go out on a limb, but I suppose IB crew to be the short form for ILL BOYS. I don’t know anything about them except they are from NRW, probably from the area Essen. I don’t have hard facts due to the members of the crew. All I have, are the names of writers which are quoted due to the pieces I found over the time. And here they are, but, as always, no guarantee of completeness and no warranty of any kind!