The first side took me about 4 hours, while the other took me only 2 hours because by then, I knew which way to carefully use leverage to disassemble and reassemble. Coil spring compressors are not needed with shorter lowering springs like these Tein S.Techs.
A difference between the stock and the KYB AGX shocks is the top of the shaft where the nut threads onto. The stock one has a hex slot for an allen key to hold on to, while the AGX has an adjuster dial and flat sides for a 10mm wrench. When you tighten the supplied nylok nut, it blocks the flat spots for the wrench. To prevent the shaft from spinning you will have to carefully grip the shaft with vise grips on a protective layer, in this case, the OEM rubber boot plus the strut bellow. Another safe way could be to use a leather strap.
On the left is the new KYB AGX adjustable strut, while on the right is the stock OEM strut
Now that the new KYB AGX rear shocks are installed, I set them to setting 3 out of 4, with 4 being the firmest. Surprisingly, the rear ride height was raised about 1 inch. After doing spirited driving for over 100 kms between Manila and Tagaytay, I am happy with the handling. At this setting 3, it is stable and firm, but not uncomfortable.