Comfort glass meaning better sound insulation was never available on E53. "Clima comfort" is what EODguy is talking about meaning IR (=heat) reflecting foil in the glass which shows as different tint especially with polaroid glasses. That foil is metallic and therefore also reduces the the passage of RF waves like cell phone and GPS signals. (The reason why clima comfort glass was never available for E39 touring with navigation because the GPS antenna was on the dash.)

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E39 530dA -02 M-Sport Messing metallic
E53 X5 3.0dA -06 Sport Stratus grey
E70 X5 40d -12 M-Sport Space grey