The IRS is not as much a bully as made out to be. And, in fact, they are quite pleasant if you're proactive. And, they are not very organized. If you beat them on the organization angle, you have a better chance of reducing your debt.
For instance, if you call the IRS to arrange a payment plan for your debt, the deal you get depends heavily on the agent you get on the phone and their mood the day you call.