About polishing the cases: there is one product (not cheap) called Simichrome that I've used for decades that also seals the surface as you polish it, and it never needs to be revisited again (at least, not since 1973...). I polished the front forks and side covers of my engine in the winter of 1972-73 and aside from some scratches from wear & tear since then, they still look like I just did it. All the other aluminum polishes I've tried (including "Mother's", which doesn't work very well despite its hype) have disappointed me with loss of gloss and/or surface smoothness over time.
One thing, though: wear sacrificial gloves and maybe pants while using it: it doesn't come off the skin easily, nor the clothes.