In February of 2013, Ford changed the mounting perch on the front strut of the Focus ST. Most of these cars are 2014 model year vehicles, but you can verify this by looking at the front strut perch on your vehicle. The 2014 strut perch seems to be flat where the 2013's have a ~3/4" tall lip around the perch.
2013 Springs required on this strut design:
The following is applicable for 2014-2018 model year Focus ST vehicles. We have discontinued our previous springs that had applied and now use the Eibach Pro-Kit springs which are linked below.
2013.5+ Springs required on this strut design: