Bad news, good news
Bad news: you hate electrical problems
Good news of a sort: it's probably your battery, and that's not too hard to change. It's your chance to put in a group 34 redtop Optima. I have a 91 318 sedan with the battery in the trunk, and the Optima won't crap in your battery box.
My wife's 2004 325i recently had the flickering lights coupled with unable to start without jumping it. Solved that one with a Duralast 49 series -- longer dimensions than the group 34 but still can fit in the trunk battery box.
Good luck with it, and let us know how it turned out.