Just finished the install of the eibach rear sway bar on my 21TH. The install took a bit longer than 30 minutes - per the eibach installation instructions - but that was with me taking my time and messing around with the exhaust.
You are required to lower the exhaust with the install. I just undid the bolts on the muffler hangers (took the side bolt out and left the back nut on by a few threads) and removed the
rubber hanger from the pipes leading to the mufflers. This allowed the exhaust to dangle 1” or so below the bottom sway bar mounting bolts. it’s extremely difficult to remove the rubber hangers from their mounts by the muffler/rear fascia so undoing the hanger bracket bolts was the easiest alternative - pictures of this method are included.
After removing the plastic rear diffuser thing and lowering the exhaust, the sway bar mounting bracket bolts and endlink bolts are super easy to get too.
sway bar bracket bolts are 18’s and the endlink nuts are 18’s but you need an open end wrench and a 8mm socket to remove the nuts from the end links. I torqued the Sway bar bracket bolts and endlink nuts to 82ftlbs and used blue loctite. I also torqued the bolts with the car at ride height - just placed jack stands underneath the control arms.
Stock sway bar is 1.1” in diameter and the eibach one is 1.4” in diameter. There is a noticeable improvement in handling and no additional NVH.