Grumpy2,

First, you have to check if your rebound springs are free at ride height. If they are free you have the right configuration. If not, the SSL front kit could be considered. But you have also to consider that the SSL kit allows to adjust and keep the clearance in the time and provides a third progressive spring which replaces the small upper rubber sleeve when the suspension comes at the full compression. The dampers provides a force related to the displacement speed of the hub, slowing the spring effect in order to avoid a "racket effect", but don't change the stiffness of the system.

I have a 2005 Plus 4 and 2 years ago I installed The SSL kit which was provided with 2 adjustable SPAX dampers. A huge improvement. In a second time I changed the rear dampers by adjustable Spax dampers improving the whole. Former rear dampers were completly inefficient (like bicycle pump), former front dampers are right, surely due to the very hard former configuration where they work only a few.

I made the work myself. You can find 2 type of reamer: expensible reamer or "normal" providing directly the final dimension . I use this second one (Librand) allowing machining the both bushes in one pass (you don't have to return the hub and use a guide):

https://www.librands.co.uk/products-view-178.html

You have to find a large tap wrench, the square of the reamer is large.

King pin replacement procedure: http://www.gomog.com/allmorgan10.html

NB: SSL kit is provided with a detailed replacement guide.

In terms of comfort, what you feel is acceleration. I don't have an accelerometer, but I made mathematics simulation models of both configurations with Scilab (freeware equivalent of Matlab). The acceleration with the SSL model are 2.5 to 3 less than with the standard configuration which could confirm the driving feeling... but it is calculation.

Regards
2005 PLUS 4