Make sure you have the right model year. Not sure if Ready Lift makes one for 2000. Check other section and you can do this cheaper with Ford torsion keys... Any way, hope the below helps.
From another forum (older model - 2006 and lower):
The stockers are 265/70/17's (31.8").
The first oversize is 285/70/17's (33") which most Z's can handle without touching a thing. You might want to crank up the stock keys.
The second oversize is 295/70/17's (33.5") which will require Ford Keys, perhaps rear spacers and a little trimming
The third oversize is 305/70/17's (34") which will require spacers, Ford Keys adjusted to level, and I would plan on a good amount a trimming.
Anything over that requires Body Lifts and beyond.
