Need help in determining what brake rotors to use
Basic rule: MBZ did a great job with brakes, so if you've been happy with your brake performance, just replace the rotors with stock.
Generally speaking drilled rotors are more susceptible to cracks and breakage than are plain rotors, while slotted rotors will accelerate the wear of your pads. If you really want drilled rotors and are hard on your brakes, then get ones that are designed and drilled by the manufacturer, such as Brembos. There are lots of people who drill the blanks, but the rotors were not designed for that even if the places do a good job drilling. If you're not particularly hard on your brakes (and don't do mountains, track days, etc.) you might get by with the drilled blanks for cosmetic reasons. (Since I'm not hard on brakes, I did go with drilled blanks for the look.)
Plain OEM rotors are all over the web, lots of sites have them, I personally like autohausaz.com, autopartswarehouse.com and parts.mbz.org in that order. For example, your stock front rotors are under $60 each at Autohausaz and that's brembo/zimmerman.
I replaced my stock pads with the Axxis Ultimates, got them from EvoBreed (he sells on ebay primarily). Very, very good pads, excellent braking both cold and hot, reduced brake dust. If you're a track man you might look at some others but for all around use I can recommend the Axxis Ultimates without reservation.
If you're thinking of a DIY I did a picture-post for E-class over in the 210 forum, virtually identical to your brakes: https://mbworld.org/forums/e-class-w210/107227-okay-brake-job.html
Take care and enjoy the ride,

Greg



