I bought an E46 M3 on the condition that I would learn to do the majority of the work, solely based on the fact that there was so much knowledge in the forums. I had very little experience working on cars, and no access to friends / family that had experience.

The forum went down earlier this year due to poor ownership – but luckily the core members revived it on a new site, and the old DIYs and knowledge are being slowly rebuilt. That forum plays no small part in making the difference in owning one of these cars a constant nightmare vs. cars that need strict maintenance on schedules that the owners have figured out over the years, combined with do-it-once part replacements that address issues in the factory design.

I used to own an '86 Subaru BRAT. I sold it to somebody on a forum I used to frequent when I went hiking for 5 months without storage for it.

Car people are the best people, and the forum for my current (utterly quotidian) ride has a couple of people who have been dispensing informed answers for years. I'm with you that small communities can be totally viable and all around awesome.

ETA: totally coveting your 70-series.