Exhaust stud removal...

[Sannox]

Also had this, tried every damn thing to get the bugger out, couldn't drill as no bits long enough and it was no. 3 cylinder, inside bolt, ended up cutting down the replacement bolt I got off ebay and welding it onto the old stud, I then had to drill out the collet hole to allow for the weld, bunged a washer on and the nut, sorted and had no problems since, the hardest part was finding someone willing to weld the bolt on.