The parts are fairly reasonable about 30bucks ea. for the lower ball joints and I think about 50 or so ea. for the upper control arm/ball joint combo. These were TRW brand.
The lower joints will have to be done at a shop that does MB work...there is a special tool to press the new joint in place. The uppers you can do, but you may need a friend for a few minutes when it comes time to put it back together (mostly with putting a big bolt back in its home) The track rod mounts (I have not replaced these) looks fairly straighforward, and may be even the easiest out of the three. When I had inside wear (with incredible feathering) the uppers were at fault. One of my lowers had failed prior to the upper replacement..no tire wear involved, just noise.
I think that the biggest consumer of $$ is the time involved with the uppers, but if I had to do them again I could probably do each side in about 45 minutes if I wasn't in a hurry (which I would not recommend being in)

-Larry

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It is a truism that almost any sect, cult, or religion will legislate its creed into law if it acquires the political power to do so. Robert A. Heinlein


09 Jetta TDI
1985 300D