I cannot remember where I found it, it was over a year ago, I think it was offered as an option once the car was in the country as an upgrade - may have been in the US too. Either way I think its a vast improvement and still in keeping with the original interior. Like your roof selection, If I ever come across a, shall we say good value one, I may get the same. I am toying with going back to the black finish on the roof and going back to satin on the sills etc - big decision there though!!!
Unfortunately the roof isn’t reversible unless you find a good condition original, and then you may as well have both. Part of the prep for colour coding the roof is sanding down the black textured plastic. Last time I checked a few years ago you couldn’t buy a new one. Sills are easily and cheaply pained black then returned to colour coded if you feel like it.