4afc-corolla

my seca can sometimes be hard to start. ie turns over really slow. it also makes a popping noise like a misfire out the exhaust when changing gears and at low revs, starts missing when i put my foot down. i was thinking electrical issue, ie battery, bad earth or could there be more to it? any help would be appreciated. oh and when the car is not running and i turn the stereo up, the speakers start cutting out. thanks guys

would anyone be able to give me any tech info on this? e.g. possibility, internal work (if needed) etc. i am looking into doing this setup so need as much info as i can get before going ahead. thank you.