My 2 cents: if at all possible, spend some time thinking hard about your speaker placement options, e.g., how far from the rear wall can you get them if switched them to the short wall ? How far from the long wall? Distance apart, distance to listening position, etc., and then take that info with you as you go to dealers to listen. Share those measurements with the dealers. Good ones will steer you away from speakers that will not perform their best in your space. As was alluded to above, for example, speakers with rear bass ports generally don't sound great if there are close to the rear wall. But even those with down facing ports, like my Revel F226Bes in my 2d system, needed more space than i was originally giving them.
With the help of brother @soix , i recently discovered how much improvement in sound experience even 9” to a foot can make.
This thread might also be of interest to you : https://forum.audiogon.com/discussions/speaker-placement-frequent-placement-changes

