Hi Allan,
Thought it was about time to say hello to a fellow kiwi (even if I am now in voluntary exile on the west island)
I have seen a couple of variations of this system when I went to Garlenda for the Raduno 500 and was intrigued by it- seems to defeat the purpose of the anti roll properties of the transverse leaf spring in my opinion.
It is more a mod applied to 500's - perhaps you could ask on the modified 500 sites- eg:
http://www.retro500.com/ I'm interested to hear your feedback- and off topic the registration of the car in your picture seems very familiar- has it spent some of its life in Christchurch?
Regards
Damon