I have the same problem with my SC4. I just had a new alternator put in with the new P/S pump. The lights flicker when brakes are applied , but i dont have the radio problems. If the car sets for more then 12 hours its dead like its being drained from a short somewhere. But the car will start great if its just shut off .The problem started for me after i installed a new A/C control unit . I think the unit must have been bad and shorted the car out, (bought it on Ebay i should have known) , so i reinstalled my old A/C unit and the car is still being drained of power when its setting over night. If you find out what is causing your problem please let me know.