haasman gives good advice, but also replace the sway bar bushings, all four of them. fairly easy repair if you are so inclined, parts are about $25-30. Can buy them via this site.

Both wagons (94+95) we have owned had the exact same noises at the exact same mileage.... really amazing how noisy considering its only 4 rubber bushings gone slack.

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1995 MB E320 Wagon
2001 BMW 530i
2007 MINI Cooper S (!)