Proper xenon lights require a high voltage power source and a self-levelling installation. I gather the latter is achieved by sensors placed on the rear axle. Fitting these requires you to drop the rear suspension. There is also the wiring considerations: it probably means taking the seats out.

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JJ Rodger
2013 G350 Bluetec
1999 SL 500
1993 E300 diesel T
1990 190