Why would you wish to alter the stock braking system?
If you are experiencing difficulties in an otherwise stock system then a rebuild is in order but, if the system has been modified (for whatever reason) and brake balance has been affected then there are several adjustable brake limiting (proportioning) valves on the market for ~$50.
The wrecking yards will yield variable pressure, linkage adjustable OEM variable pressure units such as Chevy PU or many models of Fiats plus other older pre ABS cars.
If there is a question about the ability of the stock unit to do it's job, replace it with a new OEM item. (they are super-simple but if you lack experience, leave it alone!)
As Greg points out, it is a pretty simple to test should you decide to remove it, just do the testing in an isolated area where you are not likely to hit anything!!!
Rod