Replacing them isn't that difficult. I did them on my car, and it made a nice difference. Two things to check before you do, though,:
1. Make sure your struts aren't leaking. If they are all oily and gross, you've got bigger problems than the accumulators.
2. Dissconnect the linkage that attaches itself to the control valve (that little silver looking box). After doing this, raise the little arm on the control valve up, while the car is running, and see how high the rear end of that car will actually go. This can give you a nice idea of where you would like to get it.

Hope it all goes well. Of course, make sure your hydro fluid is topped off.
Damon Fite

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1984 300TD Wagon--Astral Silver--Retired
1983 300TD Wagon--Dark Blue--Retired