Just fyi, I installed an oilguard bypass filtration system on my TDI, and love it. Its a bit more compact than the amsoil unit, and cheaper for replacement elements as well.
www.oilguard.com
We tapped the valve cover for the return line, and used one of the pressure ports for the feed line. Very clean install, took about an hour.
While the TDI is much much cleaner and full burn than the MB idi diesels, I was still totally surprised to see that after 2000 miles, my oil was still completely golden and see-thru. I was wondering for a second if I was really driving a diesel! The other day in my E300, I got the oil changed at the dealer, and by the time I got home(20 mins) the oil was so black you could hardly see thru it.