There is a TSB about the original EGR valves sticking, but 95% of the time, the problem is a plugged up pipe, where it connects at the intake manifold. I think you'd be wasting your money replacing the EGR valve when the problem is probably a plugged up hot inlet pipe. I'd try reaming out the pipe before I dropped $200 on an EGR valve.
Steve Brotherton (stevebfl) has written an article with a picture that shows where the pipe gets plugged up.
2001 E430, Bourdeaux Red, Oyster interior.
1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".