I've been debating an LM knock off as well, do you have any particular manufacturers in mind? I think a rear E46 M3 fitment would work in a square setup on the E53. Add spacers if needed.

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2002 X5 4.6is - Titanium Silver / Black Alcantara - Dinan Stage 2 - Bilstein/Eibach - Brembo BBK ----SOLD---
1993 318i - Brilliantrot / Tan - bone stock daily driver