Hi Steve,
It is pretty easy... just one trick. Jack the front of the car up using one of the proper lift points and remove the wheel. Using a couple of 2" x 2" x 1/4" plywood pieces (or equivalent) as protection, place a ~2' pry bar under the black frame and on top of the lower A-arm. You want to push the A-arm down while you remove the top two bolts which are threaded into the aluminum structure. Using the little wood pieces, place one between the frame and the tip of your pry tool and then place the other piece on the A-arm with your pry tool on top of it. (I'm making it sound hard, but it is not.) Loosen the top 2 bolts 3-4 turns each. Now you can press down on your pry tool and you can see when you are relieving the upward shear pressure against these bolts. Holding the pry tool, you can now remove the top two bolts. Again, it is easier than I've made it sound. Taking the shear pressure off is simply a precaution to best protect the aluminum threads. With the top 2 bolts removed, you can now remove the bottom bolt. The shock and coil assembly will easily lift right out.
Use a high quality spring compressor to compress the spring 25-50mm. With the spring compressed, slide the bottom perch up to reveal a round spring clip in a grove of the shock. Using Snap Ring pliars, you can expand this clip and slide it down and off of the shock. Next, you can slide the perch down and off the shock. Note: you may want to use some light oil to slide the perch down easier. Now you can easily swap shocks.... while the spring is still being compressed. Just reverse your steps.
Place the assembly back in the car. I like to use a small amount of anti-seize on any bolt we're threading into aluminum. I would recommend it here. With the shock in position, place the bottom bolt in and snug it up but don't final tighten it. Put some anti-seize on the two top bolts. Position your pry tool and little wooden protection blocks and then press down on the A-Arm to align the top holes. Run the bolts all the way in while you are holding off any shear force with the pry tool. Tighten the two upper bolts to 76 lb-ft and the bottom bolt to 129 lb-ft.
Although likely impractical for our European friends, anyone can feel free to send me a old and new shock and I'd be happy to do the spring compression and shock swap free of charge and send the assembly back to you. We have a really good machine for this and it will not scratch or mar the springs or shock.
