I don't think its a matter of taste, the car was designed to have a large rear plate, hence the plinth/appature, the same as the P5. it's totally fine if people prefer a smaller plate, and that would be a matter of taste, but I feel the "Correct" plate would be a large one.
Back to the topic, Welcome to the Forum, this is the place to be if you own a 260. (I will leave plate choice up to you)
Super Jumbo Racing
05 260 Saloon
87 5.0 Mustang G.T.
Pax? (can't say that, less than 10 characters!)
Thanks for the warm welcome guys. I have a big yellow gaudy plate on order, I like them-yes it's a matter of taste :-) I'll keep the other one so I can revert if I want to. I can't see it being illegal with the boot seemingly designed for it. Sounds awesome but the engine light came on-code reader says purge valve system. I took the valve apart, cleaned the bits and reassembled-no joy. Could be another part of the emissions system. Anyway, since it doesn't seem likely to harm the engine I've cancelled the light for now and will investigate again if it reappears!