It appears that MGW is the overwhelming favorite. There was a Barton fan and a couple of Steeda supporters but I already mentioned that any increase in NVH was unacceptable and that a shorter throw was not necessary (or even desired). And the discount for forum members makes the price difference from Barton meaningless - thanks for mentioning that. I might have stayed with stock as a couple of posts suggested if there hadn't been an option like the MGW that would give the shifting precision without the NVH.
Thanks everyone for the useful information. I will be calling MGW to order today.
2011 Pony Pkg. convertible M6
Am WS7 (sold)