I don't know if the brake pads are the same as any of the Mercedes cars, but I do know you can eBay yourself a set of Rotex Golds for a LOT less than $500. The vendor "Super Dayv's Wholesale Auto Parts" ships worldwide. He's got sets of rear pads listed for about $50.

Also, in the ebay listing, the pads are listed to fit a whole host of other Mercedes cars. Be warned though, this link is for SRT rear pads, not base or limited.

http://cgi.ebay.com/ebaymotors/ROTEX...spagenameZWD1V

Another famous brand to check on ebay is Posi Quiets. Also be careful not to get the SRT pads, as they are different size from the limited and base.