You’d be better off buying drivers and building your own speakers. Consider using drivers from the JBL 4367 or JBL M2 and pairing them with the JBL 2269 18-inch subwoofer and a Hypex NC2K amplifier for exceptional subwoofer.
Alternatively, the Celestion Axi2050 horn drivers are top-notch and don’t require a crossover, enhancing clarity and sound quality. Pair them with the 2216ND, and you might not even need a subwoofer. However, if you do use the Hypex amp with the sub, nothing else will compare. You can also make a sub box like the dual perlistan sub box. They say that box will enhance all subs used with either 2-15's or 2-18's in one box. this is the ultimate subwoofer. nothing is better.
If building the boxes isn’t for you, a cabinet shop can make them, helping you save around $13,000.