I agree that the turbo may not really be the problem. I think it's the previous owner(s). Turbodiesels definitely should be on a synthetic oil because of the extra heat, but many people probably use regular dino oil and that's why some turbodiesels are having problems.

As far as turbodiesels smoking more than non-turbos, I have to point out that I've noticed it even with my own cars. All the turbodiesels I've had smoked more than all the non-turbos I've had, at least with headlights in my rear-view mirror (which is a great way to tell). Even the TDI can lay a nice cloud when the turbo kicks in, whereas my '96 has no smoke even with headlights behind me and the 240D usually has none either. I think this has to do with the difficulty of tuning a turbodiesel to the point where it leaves no smoke behind and it still has enough fuel being injected to take advantage of all the pressurized air. The injection on a non-turbo is probably easier to control from an emissions perspective.

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2004 VW Jetta TDI (manual)

Past MB's: '96 E300D, '83 240D, '82 300D, '87 300D, '87 420SEL