I am in the process of rebuilding my entire 92z. Pretty much not a single stock part will be on the car other than the frame... so brake booster probably has 160,000 miles if it is factory, not sure if it was every replaced.

What does it do exactly? Is it worth replacing? New factory style or aftermarket style?

I am willing 4 wheel disc brakes all wilwood. What would you guys suggest?

 

Some thoughts:
1) With the cost of everything else, as you're describing it,
the cost of replacing the brake booster will be economic
white noise in the project.
2) As best I can tell, most likely failure of a brake booster is
loss of vacuum seal. (If I'm wrong on this, I'm sure other
board expertise will chime in...) Bottom line is the cheapo
hand vacuum pump for bleeding brake systems can check
this quick/easy.
3) There are aftermarket units available, but mostly for specialized
conversions, rather than great performance enhancement.
(Brake enhancement is usually accomplished by upgrading
pads/rotors, which you say is the plan.)
4) An adjustable prop-valve would nicely complement upgrades
like Willwood eqpt. There are some current threads about
p-v replacement that are very interesting/insightful.

Good luck, and post some project pics.

 

Thanks for the info. I'll search around. Pics will start once I get the car back from the body shop. I have all the parts just not the car right now..

I am getting a wildwood proportioning valve as well. I may call them up and see what they have available.