Thanks for the comment. I have the core with new o-rings, but I've only seen one thread where the hard pipes had corroded so I figured I'd get a look at them first rather than just replacing for another $110. They're not particularly easy to find which also suggests that they are pretty durable.

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2002 BMW X5 4.6iS
2003 BMW 540i/6 Msport
2006 BMW 330cic/6 ZHP
1984 Pinninfarina Azzurra