[shimarikakari]

If your team uses a gravity-based hopper the way ours does, I would recommend a spiral, since it's completely passive and you won't have to add any more motor weight. If you find that a spiral alone doesn't help, though, then you might want to add an agitator. I have to say I like the idea of mounting the compressor on the hopper - and I went and searched through the rules (starting on page 20 of The Robot), which said nothing about mounting pneumatics except that you have to use the preexisting threads. Since I assume you don't plan to drill any new holes in your compressor, that would be a great idea.