I couldn't find any instructions for the Corsair but maybe its similar to Bronco in youtube video below? (However Bronco sub is only 175 watt)
From what I've read I don't think you'll be happy with putting an aftermarket sub in there. Too many issues and variables you'll need to deal with. (buzzing, rattling, bad box resonance, bad sound by reflection, dull or too powerful for the rest of speakers, speaker running too hot which can burn out amp/sub/ wiring, etc.
The chip shortage led Lincoln to put a dummy amplifier and sub shell in there, (to meet the goofy NTHSA safety regulations). A custom box and sub might be needed since I don't know of any aftermarket company willing to spend thousands in R/D sound for just a few thousand vehicles. As you may know, the sub box is just as important as the amp and sub. Crappy resonance is a big issue with cheap boxes.
One guy used a sub out of a Ford Fusion, part fp5t-18c808-ab for his Corsair. This way, he was able to program it to work thru Forscan since other aftermarket amps didn't work, but he never said how it sounded. If you do go with an aftermarket amp, get one that is fully adjustable. Because you'll need to dial it in to match the other speakers to sound right. Also "HD radio" probably still won't work due to correct chip not being installed. Also the Corsair has the noise cancelling/reducing system, so I would think using a different speaker wouldn't work as well?
