not even sure where to begin

[r0kems0kemrobot]

so i have an 05 wrx, kenwood touch screen, 2 amps new speakers, sub, 2 farad capaciator for the sub (alpine type r 10" 1500 max watt) hid lights and optima redtop battery... now the problem

constantly when i brake my car loses power. can be as little as shutting off the radio to something as severe as shutting the car off for a brief second. even with the radio off the car will lose power, turning my lights off and restarting the car.. i have no clue where to begin trouble shooting this other than the fuse box, has anyone experienced anything like this??

[Donkey]

Who installed the audio equipment? Check you battery cables and connections. Check your alternator belt tension and condition. Your going to need a multimeter. Check battery voltage,then start the car and check the alt voltage (off the battery). Battery voltage should between 12-12.5v and alt voltage should be between 13.6-14v warmed up.

[r0kems0kemrobot]

everything but the radio was done by my friend and i, weve done numerous sound systems. best buy did the head unit and ive have tons of trouble with them (not connecting to the antenna, stealing the remote) i remember reading the hid's need relays to work properly but never found out how to go about that

[Donkey]

Check the stuff I said first. You didn't say if this was an existing problem or all of a sudden just started happening. If it just started happening then what did you recently fix/install on the car. You could have a short in the brake lighting system.