I did the front Koni's tonight with the help of Roger from NF Performance!
Donor struts for the front, all cleaned up (09 WRX).
Pipe cutter in progress.
Very clean cut!
Koni insert installed and then spring and top hat assembled.
Car back on the ground.
The fronts were a lot more work. Partially because I didn't have the right tools/setup when I started. I had a bench vice, but I never actually bothered to mount it to my workbench (more on this later). I started this install by finding the center of the strut and tapping it with a punch. I used a universal drill bit and drilled just far enough to punch a hole in the damper. It is under pressure so hydraulic fluid will spray out. Make sure to wear proper protective equipment.
So, once I had the hole made, I turned the damper upside down and pumped the piston in and out a dozen times or so. Until fluid mostly stopped coming out. I taped over the hole for the time being (to reduce the mess). Next I started in with the pipe cutter. I got most of the way through simply holding the vice with my feet, lol. Then the pipe cutter broke. One of the screws holding it together stripped out. When I went out to exchange the pipe cutter I also picked up some bolts to mount the vice to the bench. Drilled a few holes and bolted it down. Once I did that the pipe cutter was 100x easier to use. Haha. It didn't take too long and it was cut open. I pulled out the guts and finished draining it.
Then I flipped it over and got the universal drill bit back out and opened up the hole to 1/2" to allow the Koni bolt to fit through. The damper is a friction fit into the OEM strut (it has some nubs that hold it tight). You have to pound it into place, or use a bolt to pull it in. The stock bolt won't reach, so I bought a longer M12x1.5 bolt and a bunch of washers. I started with very few washers and tightened the bolt down to pull the damper into the strut. Once the bolt bottomed out in the damper I unscrewed it and removed washers. Repeat until damper is pulled all the way into place. Or at least close enough to use the Koni bolt (but I'd pull the damper all the way in with the larger bolt because the Koni bolt is an allen key and that's more likely to strip out). Torque down to spec (55 ft-lbs).
Then finish reassembling. We could not get it together without using spring compressors. I've heard other people can (maybe with different springs?). Once that is completely assembled, repeat for the the other side. It's not too difficult, but the pipe cutter takes some muscle, and the overall process is quite time consuming. We put the assembled dampers back in and set the camber bolts to max negative camber. Now that the suspension swap is complete I'll have to get re-aligned and see how it turned out. The 09 WRX struts should give me a little more negative camber than the 2011's would have.
Once we got the wheels back on and put the car back on the ground it was obvious it was lower than with the stock struts (same springs, RCE blacks). I measured the fronts at 13" from hub to fender (previously 13.5"). The rear is also 13" from hub to fender. I think it looks perfect. It is nearly identical ride height to how I had my coilovers set. Approx 1-1.5 finger width of fender gap. I set the dampers to 1 turn firmer than full soft. I think this is what Koni recommends for moderate aftermarket springs. I'm going to try it there for a while and see how I like it. I did go on a quick drive, and it feels really good. The car has so much better ride quality than the BC coilovers and still feels very planted in the turns. More thoughts will come after I've had the full setup in for a while.