If you are not married to the Pol idea, BLAM, Helix and Focal make some nice speakers.
If you can get a stock subwoofer console, the Kicker 6.75" drops right in there, so it is hidden and gives you that little extra punch that is needed. If you want to go bigger I could recommend that.
Also, my audio guy custom built me a box to fit inside the center console, and it could hold an 8" speaker. He also has great prices on the german stuff, but BLAM is best purchased from incartec. Multiple forum memebrs have purchased from here, all with good reviews.
https://incartec.co.uk/category-listing/BLAM-speakers
This is a gerat audio guy who has the German stuff, Helix, Micro Precision, Jehnert and Ground Zero. Also has the French BLAM and Focal stuff.
https://unexpectedcreations.com/