Don't give up. The DIY advice is spot on and these cars are pretty rugged and simple. Once you get everything sorted out, you'll probably only need to do regular maintenance while of course replacing the occasional 40yr old part

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63 220S W111
76 300D W115
2013 VW JSW TDI M6

previously-
73 280 SEL 4.5
86 300E 5 speed
2010 VW Jetta TDI M6