It definitely sounds like an upgrade. The original stock aluminum sprocket was anodized but still looked like raw aluminum. The newer steel sprockets are black anodized. The copper colored 'anti-seize' sounds like Loctite was used and that is not what the factory used on the rear wheel. They just torqued it hard. You may have just paid for a SuperMax sprocket that you might not need. The steel sprocket makes no noise what ever and will outlast the SuperMax. I know. I was the first to use one and I broke it after only 19,000 miles. The steel one should last as long as the car. The belt should go for about 100,000 miles before replacing.

Hope this helps!

What's your mileage? Who cares. Is it practical? See #1. What happens when it rains? You get wet.