I wouldn't touch those with a ten foot pole. Even if it is legit, You tell me how you are going to find a wiring harness for the install ? A very expensive boat anchor :lol:
Maybe you need a new battery, Or check the battery terminals and cables B) A loose key case shouldn't make a difference, But I would seek out a new key case or two, Get new batteries also. Welcome to the club
You can try resetting the ECU, Dissconnect the neg. battery terminal for 10 minutes, While you are at it thouroughly clean the battery terminals and cables. You will lose all of your settings (radio and seats etc...) Welcome to the club