DucaBike is also Billet Aluminum. Lighter but Id worry about the color turning over time depending on the quality.
xcaptainxbloodx said that the DucaBike cover is billet.
Where did you get your info that it is lighter? I weighed both and the Ducabike cover is 515 grams heavier. That is a bit over a pound.
As for the color turning over time, most anodized parts will eventually do that. Some are worse than others. And, even with the brands which do relatively better, there can be variations depending on the individual part and the operating environment. Very easy to see that at trade shows when a vendor will have their complete line on display.
The modified cover is a nice effort, but the cork seal and the AL grade would be a turn off for me.