Pretty much all the 4 inch speakers in the list fit in the sedan and wagon
with and adapter ring to hold the speaker in place on the factory lugs. The coupe is depth limited but some have figured out work arounds, I don't know the details on that .
What speaker list the one inside this thread.
http://www.e90post.com/forums/showthread.php?t=641323
The most common used are Morels and Focals next Rainbows and Diamond audio.
http://www.e90post.com/forums/showthread.php?t=343673