I’ve got a Boss MGR350B and 2 6” Infinity speakers on the sides right behind the driver and passenger seats. No XM but it has bluetooth. You won’t win any competitions but it’s loud enough to hear it outside the boat at a sandbar and while you’re running as long as you aren’t going to fast. I also like that it’s round instead of a rectangle. I personally wouldn’t have added a radio because I wouldn’t wanna cut holes in a perfectly good boat but I’m really glad someone else already had.