Get the Mugen or XRay filter setup with some [link=http://www.power-save-racing.de]Power-Save-Racing[/link] filter elements (you can get them from [link=http://www.amainhobbies.com]A-Main[/link]).

The problem with the motor saver is the front lid. Even if it doesn't fall out, it lets dirt directly to the inner filter element and maybe even past it. If you're using one, also check your Ofna header. They are sometimes cluttered up with excess aluminium because they're not welded on correctly. You might have to dremel it out there.