They are repairable so if you have the soldering skills very doable. I was going to do mine but didn't have the time (mine actually had processor issues) and ended up buying a new one so I still might have some of the relays. Your logic is sound for not getting a used one. You are way better off repairing yours or buying new OE.

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1988 325is (purchased new) sold
2004 X5 3.0 2005 X3 2.5
2008 X5 3.0 (new to me)