Originally Posted by ala_xfire

Yep, probably so. I went to the Magnecor's at 50k miles.

Here's an OEM replacement set pretty cheap with a "make an offer"
shipping will most likely cost more than the wires

Spark Plug Ignition Wire Set for Mercedes Benz C-Class E-Class ML SLK 320 350 | eBay

The Magnecor's are a bit more expensive :
Magnecor 65211 KV85 Competition 8.5mm Plug Wires