How did you know the ball joint was going bad?

I still don't think it's worth the huge cost of considering a SAS. You're probably looking at $500-1000 of repair versus at least $5000 for a SAS that's anywhere good enough quality to even consider doing it. After seeing a few of my friends do a SAS, I know that a SAS will cost much more than originally dreamed about and they usually take extra time and effort to work out bugs so they work right. So if this is your daily driver, a SAS is even less advisable.

Jeff
2000 4Runner SR5, supercharger, rear e-locker, ARB front locker, 285/75R16 MT/R's, custom bumpers & skids
2007 Tacoma double cab 4x4 - stock