I've got vintage vitreous enamel plates that are going on the 328.. was looking at how they would be mounted today at the dealership.. looks like the rear will need a custom bracket made to extend the pre-existing holes out to the plate mounting holes.. (they can't be drilled) and the front will need spacers put on as there is a slight curve in the bumper.. needs a 20mm spacer each side and the middle of the plate will sit flush with the bumper... plates cannot be bend either.. slightly stressed..
2008 135i - Jet Black, Coral, full options Procede v4
2009 123d - Space Grey, MSport 18" (decided to keep it)
2010 C63 AMG - White, custom tune, custom exhaust 319rwkw
delivered: 2012 328i - Estoril Blue MSport 19", BBK + options