A rough idle could be many things, especially if it got worse after the tune up. Did you use performance spark plug wires that you had to cut yourself? If so, you might have hooked a wire up with a bad connection. You didn't specify what type of injection, but you may have a vacuum leak. Does this rough idle cause any hesitation or loss power? Have you tried checking for computer codes through the ADLS under the dash?
As far as the humming, could it possibly be coming from the brakes? Do you have an after market stereo? Due to poor grounds near the stereo area, my stereo humms through the speakers when I slow down nd also when I turn on the windshield wipers.
Be sure to add a little more detail to your post, it will help us work through your problem. Brian