Well the section between the muffler and the front of the car is most likely the catalytic converter, not the resonator. Unless you mean the actual muffler, at the middle of the car. The resonator is at the very back of the car. So what exactly are you talking about?
Also, the buzzing at high rpm's is the pissed off bumble bees, present in every single 4 cylinder car, but muffled from the factory.
I had a straight pipe there for awhile. It sounded nice at idle and full throttle. But for just cruising around it got very annoying. No vibration or anything like that. Just a constant groan. I went with a Magnaflow resonator and made it more tolerable.