Hi Joost
The filter in the CAT is very fine and will prevent any damaging debris reaching the pump, as long as your fuel is well filtered before it gets pumped into your tanks and the tanks are well cleaned (assuming its a new tank etc) then there is no need for any additional filters.
The more restrictions you add to a system the more likely you will get problems with cavitation etc and possible leaks where fittings are introduced in pipe runs.
Safe flying and appreciate the support.
marcs