I have not looked at how the 300 is set up over my old 200d as far as fuel intake and return but a quick (kinda quick) fix on the 200 for a dirty screen was to switch the intake and return lines on the fuel system and add a clear inline generic filter in front of the stock filters. The crud was blown off the screen and picked up by the return line, then filtered out. Went through about 5 filters @ 1.99 each over about a month. Also made sure not to go below a 1/4 tank to keep from running out of fuel and it worked great! When I switched back I never had another problem, and the problem before was so bad the car would stall from no fuel.