Troy:
Was just looking through the Gene Berg catalog, and they don't recommend a combination filter/pump due to the loss of required oil flow. These combo pumps actually flow only a portion of the total oil through-put to the filter, as opposed to a full-flow pump/cover combination that blocks off the outlet hole in the pump to force all oil flow out the cover outlet and on to either an external filter or a cooler/filter combination. Having a cover/filter combination "steals" only a portion of the oil flowing through the pump to go to the filter, rather than running all of the oil flow through the filter.
The best set-up, as Ron mentioned, is an external full-flow system with just a filter, or a filter and a cooler, mounted away from the header heat, like over in a wheel well. This full-flow set-up usually requires that the engine case be drilled for the oil return line, and Berg also has a tech sheet that details how this can be done with the engine still in the car, so any competent VW air-cooled shop should be able to do it.
As Ron said, "If you want the extra filtration, have a mild motor (ie: 1776) and don't want to have the case drilled, then go for it." If, however, your engine is built up, or you really want to do this right, then go for a full-flow system.