Sounds interesting. I'm wondering what this will actually do. Alignment would be vital otherwise the BBs going to bouncing its way down that. The idea of actually having baffles is a nice one, but I do question it's usefulness given that the majority of the noise of a gbb is going to be the slide cycling. Apparently both the alloy and the alluminium one weigh the same (doubt it) but I'd consider giving the lighter one a go if it makes it's way to a decent UK retailer.