OEM Bypass Filtration ?
I'm not sure of any other model but I know that in their wisdom those german engineers have already designed and installed a built in bypass filter on my 603 engine in my 87 SDL. On this car and I assume others the oil filter has two seperate elements the lower smaller portion is the regular full flow element and the larger top portion is a high filtration bypass element of the OEM cartridge filter. I suppose adding an after market bypass couldn't hurt as long as the installation was solid. The return to an adapted drain plug! you've got to be kidding that would have to be the most exposed to damage setup and the most difficult to monitor. If you didn't constantly observe your OP gage and the idiot light it wouldn't be long after you oil was pumped out onto the roadway that some serious oil starvation symptoms would make themselves known.