One good way to avoid copyright infringement regarding Cavallino/Ferrari badges on a replica car might be to source OEM badges. The argument can then be made that if the copyright applies to the badge rather than the badged product (car) you have not breached any legislation as the badge is original.
I am however sure suppliers of OEM badges are very hard to buy from, and being a bit short of the readies for a genuine F I'll never find out.
I think (as Mr Towed stated) the difference is this: if a manufacturer makes a product and badges it as an existing (copyrighted) product he is both abusing copyright and profiting through sales being boosted.
If I buy or build a replica kit car and choose to badge it as the original I have nothing to gain financially. I suspect any issue that F have with DNA comes from this issue. Profits are being made by a replica getting leverage from the F brand.