Tesnio Strut Ball Joint Bolts
 

Have replaced the sway bar links and wishbones (control arms) trying to tighten up the front end after 117k. Figured I might as well replace the tension struts and ball joints as well and have run into a problem.

Have gotten new bolts for the ball joints, number 16 here:
RealOEM.com BMW E53 X5 4.4i Frnt axle support,wishbone/tension strut
but they are a regular torx head. The old bolts are a reverse torx head. So my question is, does anyone know the size of these reverse torx bolts? I really don't want to buy a whole set just to use one to remove four bolts and never use the set again. I would like to just buy one socket and be done with it.

use a t55 torx bit to fit in the inverted e socket which I believe is size e12