FASS, EcoPur or neither?

If you were going to get one or the other, what would you think would do the most good? Or better to just save money and not put either on?

 

Thanks for the replies. I kinda thought the same thing but wanted some other input. Seems like the oil filter would be a waste if I change my oil at normal intervals which I do, and will have to continue if I get a new truck for warranty reasons. Not sure if the fuel filter would be of enough value other than maybe polishing my fuel would help my Espar heater, but even that might not make a difference. I would be introducing another fuel pump to the system and that means another component that has the potential to give problems.
I have thought about changing the heater over to kerosene in the future to provide a cleaner fuel and eliminate some of the maintenance due to the crap fuel quality clogging the atomizer every season.