This is where I find my ole town of Klang (in Malaysia) very homely and cheap. I changed ALL the springs in the W123 and W126, together with the addition of foam (and a little of coconut husks in the W123 as I was led to believe) to butTress the seats - and the result : seats as good as new and, not to mention, firm. The total costs for each car : approximately USD80-00 (RGM300-00 @ RGM3-80 to USD1-00).
However, since my W126 has been well seated, I do find the seats wobbling a little. Not much. Just a little. I was told that this couldnt be rectified. Any truths to this statement? (I mean, it would be nicer to have seats that dont move so much.)
126 tailed by a 203, 129 leading the pack.