Anybody ever polish an aluminum intake manifold?

I've done it. Like others have said, it's a b!tch not because it's hard, it's just time consuming. You start out sanding the really rough stuff with around 180 grit, move to 320, 600, 1000, then 1500. You can keep going from there to even finer paper if you really want a mirror finish but that's where I stopped. Then start rubbing/buffing with compound and polishes.