don't recognise the make of the roof spoiler on the pic. but if i had one of that ducktail CSL deck lid, i wouldn't put a roof spoiler coz it spoils the clean looks. i recommend ACS roof spoiler which imo looks nicer and u can get the matching 3-piece rear decklid spoiler from ACS. quite sure you'd be able to find copies since it's popular. if want your car to look 'faster', get the ACS e46 m3 rear wing so that your car looks like it can run real fast. sorry haven't got pic but you can find them on the web. try to google "ac schnitzer roof spoiler bmw e46".
I don't think that piece shown in the picture is available locally. If i've not mistaken, it was custom made by a couple of owners from e46fanatics in the states.