Have you considered adding affiliate links and "buy now" links? Amazon will give you a couple % from every sale you make. Should be easy enough to code a script in to add the links when people add "buy now" links.
I don't know if that would expose the site to litigation by providing an increased incentive. A simple donation button could be arguably just to keep the discussion parts of the site online, but by linking revenue directly to provided downloads of questionable legality could possibly be seen as selling or profiting from illegal downloads. Just a thought, not an argument.
Bingo! We have a winner. As soon as someone gets a whiff that you're making some sort of profit tied to copyrighted content, they'll come down on you harder than an anvil on Daffy Duck's head.
Well, yes. Because they know that there's money there, and they (probably legitimately) would want a piece of it. As it stands now, I think we're a net benefit to Christian artists as their music gets spread more which in turn helps them sell concert tickets, shirts and yes, even albums if they turn out to be good enough to actually buy. But if we were to do this plan, to tie revenue directly to the downloads - that would basically be directly taking profits away from artists, which isn't what we're here for.