As said it's aluminum but it's been clear anodised. Anodising gives a hard finish that's more durable than you might think but if you attack it with anything abrasive you'll go right through to the base metal. That will corrode quickly unless you're willing to maintain it by polishing and waxing frequently Not ideal on a daily driver. New trim is avalable but the price is quite high. Better replacement parts might be findable. You don't say if your trim is particularly bad but with a bit of patience a good paint restorer type polish might give results that you're happy with. Wax well before putting it back on.