I'm pretty-sure they do. If not, Heidts supplies new mounting posts with their A-arms that can easily be welded on any Mustang II subframe. I run Heidts A-arms on a non-Heidts set-up. I looked at the TCI subrames and they appear to have the exact mounting configuration as Heidts.
You should have no problem putting Heidts a-arms on the TCI crossmember. They are dimensionally the same. The only real difference is that TCI uses screw-in ball joints where Heidts presses them in. That makes them difficult to powdercoat.
im actually running tci upper and lower a arms on my heidts clip they are also narrowed also the heidts and tci a arms are different in appearince but deminsionally the same the tci a arms a more rounded then the heidts ones but that doesnt mean they wont work also i bought the tci a arms due to the fact they use screw in ball joints which is good also when i got my front clip it had no a arms seems the guy sold them to some one else so i wouldve had to wait almost a month due to the fact that heidts didnt have a batch made yet so i called up tci and ordered some i even went and picked them up same day i wasnt sure they would fit but they did :yes: