Use a dremmel and in number 3 you will see there is a lump. Just grind that flat. You can go along and open all 4 up a little and just give them a general clean while your at it. As for the stud. Whats in the way? Im assuming you have the hot pipe off the turbo? Make sure u have a socket, extention, Universal Joint and a spanner and you should be able to get everything off.