I don’t have this setup, but here are some things that you need to do, in my opinion, to have good working brakes.
For good manual brakes, replace your front calipers with aftermarket stock replacement calipers form U.S. Brake or Afco. These come in the standard bore 2.5 inch and big bore 2.75 inch and bolt up just like the stock calipers. I would do this upgrade first or you will be chasing down spongy brake issues that are caused by the stock low drag calipers. The cheapest place to get these calipers, that I have found, is http://www.speedwaymotors.com .
For most manual brake applications, I would go with a master cylinder that has a bore diameter of less than 1 inch. The Strange master cylinders that come with the TRZ kit will, more than likely, be too large for your application. I would go with a Wilwood 7/8” bore master. Though it is expensive at a little over $200, it will bolt up to the TRZ adapter and comes in the popular GM brake line outlets.
For you rear disc brakes, the proportioning / combination distribution block will have to be modified for rear disc. The stock distribution block has a 10 lb residual valve in it that keeps some pressure on at the rear wheel cylinders. This residual valve will need to be removed because the rear disc systems do not need this residual valve. There are some companies that do this for you for about $30 less shipping. Here is a link to one I know about. http://flynbye.com/catalog/i67.html .
