Audio is all about comparing and testing. To create an external crossover you need the right skills.
When you want more controle and drive I would advice a more powerfull amp.
I owned the XA30.5, XA60.5, XA100.5, X250.5 and now the X350.5. I use it with the Purist Audio Limited edition. What this powercable does is impressive. The difference between this powercable and a 500 dollar powercable is this big that even a Pass Labs worth twice the price will not create this endresult. Most people who have this a s a hobby often use a low % of the whole quality of an amp.
That is why I use blind auditions to make this clear. Audio is in my world about facts. The best endresults wins. This is the only thing that counts!