Sway Bars

My parents were hesitant to buy me this '93 GC that had a 5" lift and 3" tires but they finally did. My mom said that if we bought this vehicle then we would have to do everything in our power to fix the "swaying" of the vehicle.

My main question is how much does the sway bars help on a 5" lift?

They will reduce body roll when cornering but won't do much for the sway you have while driving straight. That is usually a sign of worn control arm/track bar bushings. If it feels like it's wandering all over the road then I'd check all of your suspension bushings before buying an ADDCO or other HD sway bar. The stock sways are a bit on the small side and if you drive aggressively then a larger bar might be nice. It could also be worn steering components like tie rod ends or ball joints. A bit of advice if you haven't driven a lifted vehicle before is to take it easy the first few months. They don't handle like regular SUVs much less like cars. This is particularly true with Grands lifted more than 4" on short arms. You may want to check nagca.com They offer some good info for those with lifted Grands.
ByronP