Charlie, there are two ways you can go; one is to have the case machined for an remote filter ( usually the motor has to be apart, but not always), and a filter/oil pump combo. The filter/oil pump combo takes the place of the stock oil pump. The remote filter is the way to go, but if you have a near stock motor and don't want to have it taken apart, then the filter/pump combo will work. I put 115,000 miles on a near stock 1600, with no filter, and it was still running fine when I sold it. Almost all aftermarket VW parts companies sell both set-ups.
Ron