I've driven my grand prix without the front sway bar for over a year and decided to finally get a new one.
I knew this would be a biatch to do because it was biatch to get out. So after struggling for 10-15 minutes trying to put in in through the passenger side:
1. Take the sway bar under the vehicle with you.
2. While underneath the center of the car, put the driver side in first, push it through an extra foot or so obviously, then slide it through to the passenger side.
3. You may need to remove the passenger side tie rod end.
Took me about 1 minute to get it through this way.
Make sure you have a ratcheting wrench for those dang bolts that hold the bushings in place. They are a godsend.