Call me a bit manic, but I used to work on helicopters so have an acute appreciation for all things hydraulic and hygroscopic (and I'm not an engineer so I usually go the cautious route).
However, I should have mentioned that the reason I trashed the first reservoir (on the 500E) was primarily because gunk of some variety was collecting at the top inside part of the reservoir. There was no way to swab all of it effectively, and since it can be a complete mess replacing the reservoir I opted to proceed, but to suck everything out first.
When I removed it, I was a little bothered by a small amount of rust that was collecting at the input into the master cylinder. So, I decided to yank the 300TE's too, and in that case found no such rust. However, the cleaner reservoir I liked, and since I power bleed mine regularly they will stay that way.
"If everything seems under control, you're simply not going fast enough" --Mario Andretti
1995 E500 street car
1986 Porsche 944 Turbo S track car