Read this first.
http://www.e90post.com/forums/announ....php?f=172&a=2
now as far as reflectors go there are numerous sites, threads you can get them from.
http://www.**********s.com/OEM_Paint...9X_3Series.htm
^^website
http://www.e90post.com/forums/showth...nted+reflector
^^^thread
Just a few to start out with but there are a lot out there.
Now for DIY...
http://www.e90post.com/forums/showth...nted+reflector
^^^ this is for a e92 but pretty much the same thing.
Remeber Search first. its your friend