I have a racor unit fitted, i got it when i went to the Tdi engine. It has saved a lot of gunk and water from getting to the engine. Its a bit expensive but the cost outweights the things i have found in it, peace of mind to be honest!. It may also be fitted with an in cab sensor for water level. It also has a pump primer on top (very weak and unusable IMO). A good investment if you get bad fuel batches!!!
Grem