I had a E53 diesel, an early one and am now on an SD and to say they are like chalk and chease would be an understatement. Nothing much will ever pass you if you dont want them too. The sinc turbo set up makes this one of the true grat engines, if brass is an issue forget the sat nav and get the better engine, i did and never regretted it. I would never have used the st nav but every time i'm out in it you use the extra surge.