The tensioner pulleys are different depending on if you have the hydraulic or spring tensioner. There are 2 different idler (for the main belt) pulleys as well, one offset and one not, so something else to watch out for. There is only one A/C tensioner so that shouldn't be an issue.

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