Well, one of them (a small thin, black plastic hose) is a vent line, coming from the vacuum valve. It goes into the firewall, to nothing, I have mine going into the engine bay, my mechanic said that is okay too. I posted a similar inquire early this week... And the filter looking thing is a vapor filter I believe. Not a fuel filter like I used to think... Hope this helps your situation, one thing is for sure, who ever said the 300D is a simple car never took a good look at the vacuum lines...