[SteveAus]

These parts are expensive in the dealerships.
Have you tried getBMWparts.com in the US? They are about half the price but shipping to Oz can be a little difficult. Someone told me that you have to arrange shipping yourself....I don’t know if this is true as I haven’t actually ordered parts.
However, when I was initially looking at the G20 almost a year ago, I was quoted $10,000 for front and rear spoilers and a rear diffuser.
The same OEM parts on getBMWparts.com were around $3,500 USD.

I was fortunate when ordering my M340 and negotiated the OEM aero kit to be included free of charge......my argument was that the Merc C43 had the aero kit included and I was seriously considering buying it in place of the BMW.