Metallic prints are not for all types of photos, I did this shot on the Red River Metallic paper and it did not pop as much as my other metallic prints.
But it did give it a different feel and effect, but not the true effect of metallic paper, now on the other hand I did this on a 20x30 metallic paper from mpix and it really did pop.
Also did this pelican shot
and man did it rock, the detail in the hairs and the eye came out in the metallic paper but like the others have say it might not turn out to your liking. So maybe if you post an example of the image(s) you were thinking of printing on metallic paper we could give you some insight from that.