The only way you are going to make the legal, champ, is to have them either imported as a homologated part, at the time of vehicle manufacture and testing or to have it independently tested...
And.. unless you are going to put your money where your mouth is, and pay out that sum to have it done for us all, you have done nothing for this thread.
And yes, we see people espousing the same one-liners, 'Carbon Fiber IS LEGAL'..
I, for one, am sick of this bollocks... sure, you may have seen a lot too, but over the years I have heard every pipsqueak know-it-all tell us something, that when we ring Transport, we find out their lack any knowledge or basis...
Why not, next time, come into the conversation with a shred of proof (something written from a Department with some authority in these matters).
I promise to sit up and notice, then....