To get back on topic a little bit, currently our system is so that you have the perks for a limited time. The perks you get are pretty good compared to what regular users are able to do and we do have a list of all the perks.
We did have a little brainstorm between staff members for a tiered donator/premium kinda dealio where each tier would "cost" about 10$ more. We'd have 3 tiers, each with their own perk list. The highest tier would have the best perks on the site in regards to dl speed, limit, waiting time, post / profile stuff, etc. The big difference with these is that they'd be life long upgrades instead of bi-monthly donations.
We as staff get plenty of negative rep too and it just reflects other member's opinion towards what you posted. Some don't want to post but still show they don't agree with what you say, so they do it via a negative point. Rest assured, your -6 rep won't have much influence in future posts or our opinions towards you as a person.