I just put in the DS from driveshafts.com into my 115. Works well. They offer a rebate if you send the core but I kept mine just in case.
After the first installation, there was some vibration between 40 and 50 mph. I loosened the center support bolts, shook the driveshaft back and forth and where ever it settled, tightened it up again, problem solved.

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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