Bah. I was hopeful, but it's just as slow. Even having multiple import covers feeding into one pipe section, the rate is still limited to 1 stack/second.
It isn't the end of the world, but it would be nice if it could change
Have you tried inputs to multiple sections of pipe? If you can't find a situation where a smaller pipe gets clogged while a larger pipe works normally, there isn't much reason to have different pipes. I'll run my own tests when I get home, but it's gonna be hours before I'm off work.
Also, maybe try to lengthen the pipe? I don't know how that would change things, just throwing it out there :-/