I checked with my local dealer as my car arrives in 4 weeks.
Was quoted $154 + GST for each side ($308 for both)
I decided to order mine from Kelly BMW's eBay store. Also bought stainless steel pedals.
$120 USD for both grills - shipping was approx $40 (including pedal covers)
Perfect service, communication and packaging was legit.
http://www.ebay.com/itm/Genuine-BMW-...item417ef191c8
http://www.ebay.com/itm/Genuine-BMW-...item3a8e3ce392