ok first off the cosmos intake is metal not plastic don't assume, and 2 yes it does have some rust in it, mine did, but mine wiped off. Let us know how the install goes if you need any help i'll try to explain it.
Why would the conforti look better also? With the Dinan and Cosmos I think it looks cleaner as it almost looks like it could have come stock minus having to relocate the horns, because all you see is a black pipe in the engine bay.