Hey Guys, any recommendations on where to purchase front rotors and brake pads ?
Looking to replace, thanks for info.

I also have a 2014 E350 Sport. The front brake pads needed replacement about 60k miles. Rotors looked good and there was no pulsation in braking. I just replaced the front pads (without turning the rotors) and have been very pleased with results. Akebono makes the brake pads for Mercedes and I just ordered the Akebono instead of the Mercedes part. Pads were about $100.

If you want to change the rotors as well, there are many vendors on Ebay that provide good quality OEM quality rotors. I have had good success with ordering complete rotor and brake kits off Ebay for other vehicles I own.

thanks, I will look into ebay and amazon.
reason i want to replace the rotors is because i get small vibration when braking.

Rockauto or autohaus , and recently ive been pleased with carid.

FCP Euro is another source if you are looking for oem type parts, in my case I went low cost route and since then have had no issues. I was originally thinking Zimmerman rotors and Akebono pads but I've been fine with the alternate selection I made.
My Brake Stuff

I got rid of the drilled rotors and went with solid blanks, just my preference as I don't see much advantage to the drilled versions in regular traffic. Not saying everybody does this. One thing about drilled rotors if you prefer them, try to get them with cast holes and not drilled. Cast typically have chamfers at the holes, drilled versions may not be be chamfered and can lead to cheese grater action on the pads or get small chips at the edge of the holes.
I would also suggest flushing out the brake fluid at the same time you do the brake work. I use a Mityvac at each caliper and replenish the MC, some use pressure bleeder.
I loosen the bleed screw as I compress the caliper piston to avoid pushing old fluid back into the lines - that's if I change pads without a brake fluid flush.