I am planning audio for a 18 1/2x15 1/2 room with a built in. Was thinking of buying a Denon 2808ci and wanted to match it with some bookshelves and a center channel to start, possible sub, rears(likely in ceiling) in the future. Do I go Sierra1 or CBM-170 with CMT 340-SE C? Thoughts..... Also placement of speakers relative to the built in config. Thank you!