Jim,
I have used the NU-CAST and it did a reasonable imitation of cast alum. I would media blast, but with something that doesn't take the cast look off, then (after experimenting a little on somethng else) shoot lite coats so the cast alum. will come thru. With all of the pieces on the Cad. intake it should look good. Besides, the cost is very little if it is not to your liking.
Jim