For others that stumble on this thread considering H&R springs. I had my H&Rs installed yesterday (best they could do on the alignment was -1 rear camber) and when I get a chance I'll check out the below...
I reached out to tech support at SPC and they mentioned 2 points:
1. If anyone is in the Colorado area they would be open to test out the correct part that would fit on the 2020 ST if someone contributes a test vehicle.
2. Based on the line drawings of the Explorer ST suspension it is possible the following existing part may work (see my pasted reply from SPC below):
"Here’s the link to the Mustang rear upper adjustable control arm part # 72370:
https://www.spcalignment.com/index....part_description&pid=72370&Submit_form=Submit
Please compare it to your Explorer, taking note of the cone shaped mounting surface where the outer end of the arm contacts the top of the knuckle. I would hope this matches your Explorer.
The center to center bolt hole dimension of the 72370 is a range of 284-271mm (11.2-10.7”). The mounting hardware which goes through both bushings is 12mm. The inner bolt is 70mm (2.75”) long and the outer bolt is 100mm (3.9”) long. The inner bushing width is 40mm (1.57”). The outer bushing width is not critical for the Mustang application because the bushing is not cradled on both sides by the knuckle."
