What I noticed immediately after the MM T/A went in was the feel of the car changed completely. The rear end just sort of followed along instead of acting like it was fighting the front end. Kind of hard to describe, but this was noticeable even at quite moderate speeds on curved roads.
Interestingly, the rear of the car actually rolls more with the T/A than with the 4-link. I had to space my (10 1/2") rear wheels out a 1/4" to avoid contact with the inner wheel well in roll. This is due to the MM PHB which now controls the rear roll center and lowers it quite a bit and possibly also to less bind.
I also found the T/A added a fair bit of understeer at auto-cross speeds. An MM adjustable rear stabar took care of that.
Nevertheless, the improvement is immense in both feel and grip. I can't imagine owning another stick axle Mustang and leaving the 4-link in it. Easily the best change I have made to the car.
Mustang - The Great American Kit Car
#50 ESP/SM2 (backup) - Cal Club
Porsche - The Great German Kit Car - #50 SM2 Cal Club - #84 JP PCA