I could read this thread for hours lol
awesome writting style, and VERY nice rescue on that that little bronzit e30!
like others have said, these cars are VERY addictive, and are somewhat easy to work on...much like Lego if anything.
coolant temp sensors will yield fantastic results when replaced, they are like the e30 antibiotic. They devise excellent outcomes when they are at fault.
M30b35's are the last of BMW's notoriosly awesome "Big 6's" a few guys on here have swapped them, and with only 107K on that one you're barely even close to breaking it in.
All the best, and enjoy the fruits of your labours!....which, evidently come along with Bentley manual studies, Maxbimmer, E30tech, R3vlimited and Bimmerforum discussion in which these cars are disected through and through and inside out again and again.