do a search on this topic, lots of info on this site
1. Bilstiens shocks for smoother ride
2. Anti sway bars by Roadmaster, etc which connect box to chassis better for stability.
3 Steering stabilizer which holds front wheels in straight line to help stabilize steering.
4. air bags only help more for towing and heavier loads in back
steering stabilizer would help most for your situation but all three work together and really do make a big improvement despite what others may say. cost about $3K for all.
5. then have it aligned because if you have it aligned first and then do the mods, it might throw alignment off .
i had the exact same problems with my first unit. once I did the research on this site and did these mods, it drove beautifully.