You can clamp the fule hoses to the fuel pump/filter assembly with some small size carpenter clamps, it can save you a big mess.
Don't know about 300E, but for my 400E, i need more copper gaskets besides the fuel filter kit I got, those gaskets can only be used once, fuel pump/filter use almost a dozen of them.
99 BMW 540i 6-speed 110K Km
03 SAAB 9-5 wagon 80K Km
92 400E (Sold) 245K km
Still missing the days with the Benz, it kept me busy.