Chris--thanks for responding but the bolt is way to tight to take loose with an open end--and besides--the bolt sits in a recess with a small angled "shelf" above it and very close quarters to either side and below so the jaws of an open end is not likely to be usable in any case. The "shelf" tends to push the wrench off the bolt head leaving just a small window of movement.
KlausC--thank you as well and because of the "shelf" an offset wrench will likely be the only tool which will work (the only angle available to hang a straight wrench will allow a cheater bar but no room to swing a hammer). I'll have to visit a "real" tool store (luckily one only 20 minutes from home) to see if I can find an offset wrench with a 6 point box end. HF only carries 12 point offsets. Then I'll give the bugger some good whacks as you -- and Art have suggested (in other posts).
My son Daniel (MINi-Cooper tech here in Winston-Salem) agrees with you -- didn't think the stud would be removable.
BTW--The motor mount was removed completely with support from underneath. The cast "bracket" has to come off to allow the TB to pass. Will report on progress (or lack of) late next week. thanks guys -- Dave