When I did my conversion (link in post 73) I didn't weigh them,
but the aluminum arms are much heavier. The difference with
the calipers is that they are mounted on the front side.

The anti-squat bar (sway bar) is a direct bolt on for a 126,
The larger bolt holes are under the existing sway bar brackets
and have rubber plugs in them.

I am very happy with the results. Car handles better and there is
no more bottoming out like I used to have. I have a spare 12 gal
fuel tank in the trunk which adds a fair amount of weight.
I pulled everything from a 500SEL.

Jeff

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1984 300SD 300,000 miles--two tank WVO setup
2.88 diff & 500SEL anti-squat rear end