If you want the shortest possible shift you'll have to trim the underside "ring" on the edge of the shiftboot because like you said, the cable will hit it when going into the up gears. Its simple just to grind/melt/file off a little and you will not have problems.
It is not an adaptor, its a full lever. I think they are priced just right. Its not expensive at all when you figure a Civic/Integra one goes for $120ish and it is a lot less material and less complicated design.