80mm alloy pipe won't fit well in the stock configuration, and I can't find mandrels in that size. As it is the same size as the AFM it just seems smart to keep it similar for flow, and 80mm silicone is readily available now.
3 inch pipe may just fit to the stock airbox with alloy donut bends but there is no way (currently) I can make them the same every time, manufacture them remotely and guarantee they will fit. It's quite hard to make a product and ship it across the country without making sure it is consistent, I can only do that with the lobster cuts.
If you needed shiny mandrels you could take your car to any of the fabricators on here, they would be happy to make a stainless or alloy version for you as would I, or make it yourself by all means. Will it perform better? No, it's only for looks, and if you don't follow the few basic rules in construction you will have all manner of issues with it. (unless you go map sensor and ditch the AFM)
PM me with your ideas if you like and I will run through the basics. Stay away from silicone bends as when hot and soft it will suck in and put you in the same position you were with the stock intake.