Try getting a part number of any of the parts and sticking it in Google. It should give you a good start. If it's genuine BMW, Realoem is your friend.
Do you mean the calipers or the disc or both? I think most e46's had 325 mm diameter discs. Although, they would have to converted to 4 lug design of course.
I don't think they are e46 calipers. Here's a photo of mine on the front of the 330xi.
Cheers