During the course of an NHTSA investigation into the MT-82 six speed manual that was available in the 2011 and 2012 Mustang, Ford seems to have figured out what they've done wrong.

So if you've got one of these,  and have had problems with cold shifting, increasing difficulty in shfiting, grinding in 5th gear, or the clutch not engaging over 4k RPMs, Ford has an answer.

http://mustangforums.com/articles/industry-news/nhtsa-ends-mustang-manual-transm...