Jase,
They will be made of fibre glass and will see about getting them done in carbon fibre but when in carbon prices rocket as the price of carbon these days is so exspensive. As for price i will have a closer look at the diffuser to whats involved and speak to my metal blokes about fabrication and will let you know.Will try and keep price down as much as possible and quality is the best othawise i wouldnt do it, dont accept sh... .