Have you considered, that maybe you are moving the wrong direction from the best sound you will be able to achieve for your budget? I immediately thought of some great choices of two way speakers in the $10K to $20K range. But absolutely not in the $1K.
If you have a budget system and want to get the best and coherent sound (matching a two way with and 18" subwoofer is going to be hard)...I’m just guessing this is not a $12K subwoofer. Then your very best bet is a normal dynamic tower speaker. You are going to get the best, most coherent sound from thing. There are dozens of companies producing very good speakers, especially used. B&W, Sonus Faber, Focal, DynAudio... etc.