Hi Ken,
I have done 52k in mine now and only had a cat go ( quite expensive ) but you don't need the rear two and can just replace with a pipe if you were unlucky to have one go. Also you can extend the warranty up to 7 years 80,000 miles, it is quite expensive but is a full manufacurer warranty ( see thread on this info for UK drivers ). All of the oily bits are Mercedes and have a history of reliability. It is a lot of car for not much money !

let us know how you get on.