I went with Arnott bags years ago, zero issues / complaints. Gotta get the -comfort- ones though for the 4.8. Key thing there.

I recently did replace the rear shocks with Billy B4's. Again 0 complaints and rides like stock... And I know dam well since my OEM with 146k shocks were in impressively good condition still.
It was more of a "While I'm here" as I was doing the rear trailing arm bushings.

Alternatively I drove a friends rebuild 4.6 (single axle air) with Bilstein B6's. And GOD was it stiff. But I think that plays more to Non-Dual Axle air X5's from my past expirence.

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2004 BMW X5 4.8is [Black Sapphire] / [Black Nappa] [Nav] [DSP] [Style 87]
2003 BMW 540i [Sterling Gray / Gray]
[Msport] [Mods from A-Z] [Two-tone Interior]