The kit was purchased through Strafe Automotive in America (http://strafeautomotive.com/home.php?cat=252)
The kit is all replica so fitment issues is always an issue however due to the fact that its from the US its pretty perfect. The rear has no issues at all, the front has a slight issue with one of the indicators on the side not fitting properly and the sideskirts aren't as flush as they could be.
The rear diffuser is Carbon, yeh - other than that, a good quality fibreglass composite from what i can tell.
On another note. I have my car booked in to be repainted on the 14th on November. Going for a Lambo / Audi Pearl White type color. (A little brighter than IP)