...about the stiffness of the rear suspension on my MY03 wagon with 45Nmm springs on as I have sorted it out with that often forgotten adjuster that controls rebound. Four clicks of increased rebound damping has stopped us having to brace our buttocks before each speed bump or pothole.

Trying to rationalise it quasi-scientifically I presume as you go over a bump the springs compress a bit (though the car will also go up a bit which gives you the first jolt) and then uncompress which gives you a second jolt (though merged in with the first so you don't notice the split). Increasing the rebound damping reduces that second jolt so you only go up half as far (if fully damped).

If someone knows about it could they put me right if I am wrong?

 

Interesting observation, but are you sure you have been turning the adjuster the right way? That butt-clenching syndrome usually indicates the rebound damping is too high and so after the compression of the bump the wheels are not dropping fast enough for a smooth landing.

Are you still on Ohlins? If viewed from the bottom the adjuster should be turned fully clockwise (screwed in) to find the max stiff setting then backed out 3 clicks (to allow the adjuster to expand with heat) or more to suit.

BTW I'm using 53/48N springs with Ohlins struts on my leggy wagon and they are superb on bumpy roads.

 

Yes to Ohlins and yes to 4 clicks clockwise. The rally car they came from had 34 clicks of rebound all round (out of 40) so the backs are now thirty from fully stiff.