Yeah I know how quick they are Is this the one which has been owned by a few members on here (used to have an 'FMP' number plate I think)? You need to get a thread up!
I like the Cup spoiler optical wise but it would mean a complete swap of the boot lid in my case as it wouldn't fit the current one.
There are a few reasons why I've dropped the idea by now.
- it slightly reduces top speed but no gain in down-force (compared to the one mine came with) from what I get
- it seems to deform (presumably sun/heat related) so that some people had to put transparent rubber spacers above the third brake light to keep it from touching the top of the boot lid
- paint(ing) issues: the matt grey seems to be a difficult terrain, same goes for extra glossy black it seems
- the money it would cost can be used for more important things (like coke and hookers for example)