PB Blaster, vise grips and MAPP torch were a no go.
I found some of these and they were great with the aid of an impact wrench.
I think I will be using these a lot looking at all the rusty fasteners I have inherited
Oh and I had to make some studs from some M8 1.2 x 50mm bolts.

http://www.harborfreight.com/cpi/ctaf/d ... mber=96335
As I was using the extractors, I rounded off 2 studs too much to get a good grip. So I grabbed the hammer and mushroomed the end of the broken studs. That gave me enough grip to finish the job.
If you are working with hardened studs and can't get them to bite, soften them up with the torch first.
-=Ken=-