I'm interested in this as well. I'll be interested in hearing what you ultimately do. My father has a Ford F350 Diesel pickup that he wants me to install a bypass filter in. Got me thinking that I should think about it with my 300SD. I'm running AMSOIL in there now (just changed over), but haven't gone the bypass filter route yet. The car has just over 200K on it and I'm wondering if the payback is there for this on an older car.
1987 300SDL 265,000 mi.
1982 300SD 325,000 mi. (and holding)
1956 Packard Clipper 150,000 mi.