If you've got packing blowing out of your pipes, it is definately time to replace it. It should run even without packing, it'll just run like shit. The packing does help with the back pressure. If you roll it looser you tend to get a little more low end, while if you roll it real tight, the top end comes out a little more. Try searching on how stuff works for 2 strokes, it's basically the same concept as the exhaust acting as a valve.
Cutting the TORS shouldn't make a difference unless maybe two of the wires are now touching, and you're shorting the system. Would need a little more info, I'd check to see how dirty the bowls are, and how clean the carbs are in general, pretty easy start.