I was looking into doing this and its definitely been done and possible. some info in link below
http://www.e90post.com/forums/showth...=244858&page=2
im not going ahead with it now, (funds needed elsewhere) but i managed to get some lci tail lights which i am now selling - shameless plug below (you'll still need bootlid and bootlid lights)
http://cgi.ebay.co.uk/BMW-E90-3serie...#ht_500wt_1156