If i get 20's and new tires do i need to put new brakes on my 2000 Chevy Silverado??? If so, what are some good kinds to get?? Also, will it screw with anything else?? Suspension?? Shocks?? Springs?? Anything??

everything should be fine, braking will be marginally reduced by the heavier wheel/rim combo but not enough to require new brakes before service is normally due.

Well, Depending Onyour Tock Rims Size If The 20's Are A Few Inches Larger Than Stock, Your Stock Brakes Won't Stop You, You'll Need To Upgrade Them.

It all depends on the weight of the wheel and tire combination. If you increase the weight too much, it will increase the load on the brake system and you should look at better brake pads/rotors.