So the 4.6is rear damper is different, 33526750361. ZF catalog shows 311 233 for that one.

I tried checking your part number on the catalog and no compatible products came up.

EDIT:

Checked the Bilstein catalog, for your part number they correctly identify it as an air suspension application and list 2 options. B4 24-026529 and B6 24-107440

For a stock vehicle I would go with the B4. Per the last mention of the B6's on here I saw, they are much stiffer than stock.

B4 is your closest bet, but I have seen on my own on other cars, and read that also for others, that they may not be an exact match sometimes damping-wise. They can sometimes be slightly stiffer than OE. Still perfectly serviceable performance-wise but the difference was noticeable.

The only way to be 100% sure is to go OE. Looks like they are double the price but at least still available.

I'd try to look for any reviews of the B4's on the archives here, hopefully someone has tried it before and has commented.

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04 X5 3.0i auto
03 X5 4.6is