The glasspack is probably what's hurting ya, go with a good quality muffler like Flowmaster, Magnaflow, or Borla and a 2.25" tailpipe. I'd suggest the 66mm BBK TB, especially if you're planning on getting a chip. It won't be too big if you have good intake and exhaust.
When you reset the computer, let it idle for 10 mins before you drive it. When you're driving you can turn stuff on, just don't have anything while it's sitting there running.