If you're sure that the location you found will work, why not find a stud, with diff threads on each end to fit the needs? I know I have read a few posts where they have tried a few locations before finding the one that does work, since diff locations will pick up different vibrations and may send the KS code even when no problem is present.

I dont know what the bore hole size was on mine, but if I recall it was a 10mm (possible 12mm but no bigger) socket used to remove it. And yeah, I wish I would have replace mine when I swapped the engine out, just forgot about it. Gaskets, yes. Intake and plenum etc.... check this site, easiest place to find all that you need, I had a bitch of a time trying to find anyone local that had what I needed and had to get them from this site, but your area may have more options. At least it will show you every part you might need.

sorry I cant be of more help with your other questions, but most of what I had to do is still pretty fresh in my head if you have any questions later on.