Room: Open air basement w concrete walls, 8 X12 area is carpeted, ceiling wood rafters are 8' high. TV is 55" with my viewing BED distance at 7 feet with front speakers calibrated at 6.5' distance with surrounds calibrated distance at 4 feet.
I would keep the center and the sub, repl the front L/R and surrounds.
Budget: $800msrp for 4 bookshelf speakers.
The Polk surrounds are suspended from the ceiling with the tweeters 22" above my head and a little behind. The woofer is at 1/4 gain, as is enough base for MOVIES. I am a DD movie watcher.