http://www.ebay.co.uk/itm/AUDI-A6-C6-4F-2004-2008-RS6-look-REAR-DIFFUSER-SPOILER-NEW-NEW-NEW-NEW-/181515097079?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item2a432493f7 Wondering how easy it is to fit?