quite a few companies do shallow fit speakers
kenwood,alpine,jbl,
the one id reccomend is the rainbow cs but it does involve a little bit of messing around to fit them
other than that id reccomend focal access which should fit straight in no messing
there are some others such as dynaudio but these cost perhaps 3 times that of the others which may or may not be above your budget
there is another guy on the forum named andymac who is very knowledgable on the s3 whom may be able to give you some more options