I was thinking you'd have to throw in the towel on that BMW. I didn't want to down you, but fixing those rusted out rocker panels alone would've been a MAJOR undertaking. Probably at least 4-5 hours each side just to cut out the bad and replace with good metal, and that'* assuming they didn't find more rot. Once a Bimmer starts to rust, it'* a parts car, unless you own a body shop.
Just think of it as building character, just like hiking for hours in the rain.