^^^+1 on the venturi, have used K&N + JWT venturi on 2 cars, one for 10 years.lol, filters better than a JWT....why because its got a cool JDM name like Apexi? any gauze based filter is basicly the same...worst downfall to them is the oil you have to put on them killing hotwire maf's. foam based filters just plain out suck.
the thing with the pop charger is the large venturi design of it. normal "maf adapters" do nothing for smoothing the air. just a hole. the pop charger is a smooth curve and inlet into the maf which when mounted has little to no lip or transition into the maf so air is moving less violently.
the pop charger is about the only product i would ever recomend from JWT anymore. atleast on it, you cant really screw it up