In my experience different speakers with behave quite differently depending on placement to boundaries and distance to listing position (reflection points, nodes, etc.) The position of the drivers in the cabinet will give a wildly different presentation, as will the width and depth of the cabinets.
If you don't have a symmetrical space -5, if you don't have the ability to move the speakers around -3, add a great amp to this not optimal set +2, new expensive cables +1, etc. Obviously this isn't a scientific rating but without the first two, the (everything matters) approach with be skewed as well. Amps and cables matter more if you have the first two.
Do the best you can and have fun +10.