According to the Mercedes Benz technical centre, Milton Keynes, The Euro engines are different. It's still single but apparently the US engines had to be made lighter so the timing chain, tensioners, sprockets etc. were some of the items to be 'lightened'. They said alot of people change them every 100,000 but Mercedes themselves don't recomend this.

Didn't get it in the end, but their's another I've got my eye on although it's the 500 and with fuel prices in the UK?