Well an 044 will already have a screen so in that respect it's debatable whether a pre-filter is essential. It can do no harm though, and probably makes sense with a custom fuel cell

But certainly fitting a stainless mesh element to your existing filters would offer a huge improvement.

In an ideal world though you would then fit a proper filter after the pumps to protect the injectors.

From lots of searching, it seems their paper element is 8 micron and stainless 55 micron.
They rate the filter at a flow of 300lph max. That will be post pump and probably with the 55 micron filter where it has the pump pushing fuel through it.
The 8 Microns wouldnt be so much of an issue if the filter area was much larger. But they are just small filters and certainly not designed for efi pre pump usage.

IMO those filters should not be used pre-pump in a gravity fed situation.

If you want a cheapish option, this would be better and more suitable

http://www.ebay.co.uk/itm/SYTEC-FUEL...item1c2b7b5aee

Although it looks like a copy of an OEM item, I think some Porsche's etc used to use them before the Bosch pump ( the 044 was originally a Porsche fitment )