Bringing this back from the dead.
Since I have to remove my steering rack for reseal and repair, I took this as the opportunity to replace other nuts and bolts especially the swaybar bolts and the subframe bolts as I had them removed to install the Rigid Collars years ago - which I am told I actually had to replace the subframe bolt as it is a one time use only.
Well that looks crap...
Time for the specific rear subframe bolt for the S206:
Not only it is longer, but you can see the un-threaded section of the bolt is also thicker while the standard bolt's thickest section is at the bottom part only.
Parts required x 2
On the S206 it is fitted on the flexible arm support (or whatever it is called):
But I went ahead and decided to replace all four of the rear subframe bolt with the S206 item:
The result is even more rigid rear frame, more pleasant rear suspension control, but is also worsen NVH (this i think is because the use of 4 bolts instead of 2 on the specific area Subaru intended) in the boot area; exhaust hum and some panel rattles (now I do have empty boot and some stuff in there, and no spare tires).
So if you have to replace your rear subframe bolts; then consider these as upgrades which goes really well with rigid collar and rear subfame bushing insert modifications.