Brake upgrade, New master cylinder?

So I just picked up some calipers, pads and rotors (tundra brake upgrade s13we) and a Trail-Gear rear disc conversion kit. Already have braided lines all around and was wondering if there would be a good master cylinder I should swap in since im swaping everything else already? Or if I stay with the tacoma master cylinder is there any specific proportioning valve I should get to go with the rear discs?

 

I am thinking of performing a brake upgrade as well, swapping to Tundra or aftermarket. Don't want to spend $2500 for a race brake setup, just better stopping now that I have added 500 pounds of bumpers and armor and heavier tires.

Hope someone stops in for a bit of advice for us....

 

My master cylinder just went and it locked up my brakes in the city. Not a good experience. It had 207,000 miles on it and my mechanic had just replaced all the routers,calipers, and drums in back.

 

With the Tundra caliper upgrade, a MC upgrade is not necessary, from what I have read.

With a rear-disc conversion, I don't know. Ask the vendor.

What is the reason for the upgrade? Going to larger-diameter tires?