Being that your profile says Sydney, might want to call into the RTA.
I'm almost positive that a fiberglass bonnet will need an engineer's certificate to make your car roadworthy.... if even possible at all.
Metal under stress BENDS. Carbon fibre under stress SPLINTERS.
Pretty sure that's going to influence things a little .
Unroadworthy = no insurance = nightmare loophole that ANY insurer will take advantage of to avoid a payout.
Don't get confused with dealer warranties, where aftermarket parts have to influence a factory part some way for it to fail for them to try and wriggle out of a claim. With roadworthiness, you either ARE, or ARENT. And insurers love taking premuims every year from car owners too silly to realise that its a waste of money with their modified car.
Just a nightmare that isnt worth it man.
But if you dont care about being insured, go nuts. Plenty of suppliers out there that will happily take your coin so your car looks pretty.