Troubleshooting:

Strut Shaft Nuts - Remove the adjustment knob from the top of the damper using a 3/4" or 19mm wrench. Next insert a 5mm allen key into the strut shaft to prevent it from rotating while torquing the strut shaft nut down to spec.

Spring Preload - The preload at droop should be 4mm for standard coilovers and 7mm for the separate adjustable shock/springs rear set-ups.

Strut Lower Lock Collar - If these come loose, the threaded dampers bodies can 'knock' around within the lower mounts. These can be snugged down with the spanner wrenches, but the final tightening should be done with a hammer and flat punch.

End-links - Check for looseness and extra play in the end-link ball joints. Sometimes, if they are installed clocked and not at the center of their motion range, they can be damaged prematurely.