Here is a walkthrough for installing Konis paired with Epic Engineering springs (a FBP exclusive!). This walkthrough is structured based on working with an extra pair of front struts like the ones I bought off this very forum.
If you don't have an extra set of struts you will need to remove your front struts and break them down which increases the amount of time your car is on jack stands. Either way you will want to plan on a full weekend to do this project at a leisurely pace. Someone who has done it before and has an extra set of cut/painted/prepped Koni fronts would be able to knock this out in a few hours.
Without further ado...
Post #1 - "Cut-a-strut" Installing the Koni shocks into the front struts
Post #2 - Installing springs onto the front struts
Post #3 - Installing springs onto the rear shocks
Post #4 - Installing the complete assemblies into your vehicle
Post #5 - Installed pictures
1. Secure the strut upside down in a vice. Using a punch, mark the center of the strut tube to make drilling easier.
2. Use a 3mm or 1/8" drill and drill a pilot hole. Be aware that this tube is pressurized and drilling in this position will cause some fluid to escape in a quick spray. On the two sets I have built this has been very minor, but I would recommend you keep a shop rag handy and wear eye protection.
3. Turn the strut over, drain the fluid into a bucket and dispose of it properly. Clamp the strut on it's side and measure down from the top of the strut body according to the directions. I used a scribe tool to mark the strut body in a couple of places at the 40mm mark.
5. Cut the strut body using a hacksaw and a good blade. The wall of the strut is ~2.5mm thick so you have to be patient and work your way around the strut to get a fairly straight cut. I use a piece of masking tape to help me keep the line.
6. When you have completed the cut you can remove the shock insert from the strut body. At this point you will want to go back and remove any heavy burrs from the cut with a file. However, it doesn't need to be perfect as you will be installing a rubber sleeve over the cut (shown later).
7. Now you will need to drill out the 1/8" hole on the bottom of the strut body to it's final size. The instructions call for a 14mm (9/16") drill but I was restricted to a 12.7mm (1/2") drill due to the chuck on my cordless drill. This worked fine for me, but your success will depend on how centered you placed the pilot hole to begin with.
8. At this point you can either proceed directly to installing the Koni inserts, or you can degrease and paint/powdercoat the strut bodies. I spent ~30 minutes cleaning the struts with turpentine until they were clean, followed that with soapy water and a rinse, and let them dry. Once they were dry I hit them with 3-4 coats of Rustoleum semi-gloss black. You've seen the before pics above... here's the after:
9. Now we are ready to install the front Koni inserts. First place the included rubber sleeve over the cut end of the strut body.
10. Insert the shock unit into the strut body. Apply a small amount of threadlocker (Loctite 242 or similar) and thread in the bolt/lockwasher/domed-washer in the orientation shown, into the shock through the hole you drilled. Using an 8mm hex key, tighten the bolt. You will feel some resistance as you draw the shock insert into the strut body (assuming you cut it right!). When you bottom out the shock in the strut you will feel it.
11. Torque the bolt to the required 55 ft*lbs. Repeat for the other side and you are ready to move onto spring installation!