JWerion...not aftermarket but OE Porsche, still avail from the race parts div -Werkes 2, accross the street in Stuttgart from the main plant. This unit is lubricated off of the OP galley, has a greater airflow delivery ratio (compared to the earlier units) for excellent engine cooling and is tried and true.
I use a horiz fan unit is on my six. The cooling airflow rate @ 8,000 rpm is 1,400 litres per sec, while the fan is only turning 7,000 rpm . These are P factory specs--PM me if you want them emailed to you, as this BB can't load up the jpeg
Marty