Without a doubt, the very best way to get high quality bass from your speakers is to replace the electrolytic capacitors in the crossover of your woofer driver with teflon caps.
https://solen.ca/product-category/capacitors/
You simply replace them using the same value and voltage rating (higher voltage is OK, but not lower). Since you won't have enough room in your speaker cabinet, that will be a problem you'll have to solve.
Being an audiophile ain't easy.