DJ Qube

Assuming going from a stock brake setup to a Big Brake Kit would require me to get a 3mm spacer to clear the caliper, does that mean my rim / tire would extend outwards a total of only 3mm, or does a BBK rotor / hat setup have a "thicker" mounting depth than a stock one piece rotor, therefore pushing the rim / tire out even further?
Also, with the stock bolts, is there a general rule to how thick of a spacer you can run without needing extended bolts?

DerrS2K

Many rims require more than a 3mm spacer to to fit a bbk. Rotor hat thickness is typically the same as stock so the rim would only get pushed out the width of your spacer. 5mm is about the max you can go with stock studs. Personally I would only run stock studs with a 3mm spacer or smaller though. Some larger spacers come with studs attached that allow you to use oem studs with them.