I ran a generic universay BGW that I bought off ebay a few years ago on another car. The one I bought was full carbon and quality was spot on. The legs you can buy seperately if you want to go higher and is a piece of wee to fit. Easy way is to mask off where the legs will sit onto the tailgate. Screw the bolts onto the legs and dab on some paint onto each bolt head. Get another guy to hold one end whilst you hold the other. Slowly lower the whole assemble onto the boot until its sits at the correct position. Once on, lift off. Do not move around. you are looking for 4 paint dots on the masking take. These then are your drilling points. Drill from top down, seal the holes with mastic, take off the maskin tape, offer the wing legs down and bolt from the underside. Done. easy.
this is the wing I bought which they are still selling:---
http://www.ebay.co.uk/itm/57-3D-3DI-GT-JDM-Universal-Carbon-Fiber-Adjustable-Rear-Wing-Spoiler-New-TOP-/291523294092?hash=item43e024738c:g:XVoAAOSwLVZVs1Mk
quality is great and are very light. Legs are alloy or forged aluminium. Make sure to add spread washers washers to the underside of the boot lid.
Not for everyone the yanks love em.