On a 458 that I keep clean and polished for a guy I have never had to touch the Engine compartment.
And the heads are wrinkly Red, they don't even seem to get dust on them.
yet you would think with the exhaust from a rear engine car it would be covered in dirt.
maybe you need to throw out the colours that you definately don't want as at the moment you can't breath for choices:)
I think your forgetting it's a Jag, copying what has been done on a Ferrari will look wrong IMO