I did V6 rotor swap recently and still use the original MC. It works fine for me. I have heard if you also put discs in rear you will absolutely NEED the 1" MC.
I have also heard that upgrading the booster makes the biggest impact on brake feel.
I'm okay with a soft feeling brake pedal. They still easily lock up if I need them too. Some times too easily, so for now i am glad I have not done the MC and Booster upgrade. But I am sure I will do it eventually. Gonna jump to 37's for next tires and will probably do rear disc swap and redo brakelines and LSPV so I figure I'll end up with all new plumbing and the MC/Booster upgrade at that time as well.
So....booster is only required if you still feel like the pedal stroke is too long or 'slow/soft'. If you are used to a sensitive/short stroke pedal or prefer that, I would do the booster as well.
85 4runner, Armor, Winch, 35's, Dual Case - just so you know what weight im stopping.
