I have a 97 E320 and the seat has the same problem. I already filed a report with NHSTA. Like apb, I urge all W210 e-class owner to do the same so it can be recalled (hopefully).
colinc: Glad you mentioned the "water in the rockers" problem. I have driven two W210 e-class cars and both had the problem. I test-drove a 98 E320 and it had water in the rockers after the dealer washed the car so I did not buy that one.
I bought the 97 E320 and after owning it for about a month (after a car wash), there was water in the rockers. I simply cleaned the drain and the water came right out and it had been fine ever since. There was a few small leaves in the drain holes.