after market speakers

Hi all, Following a largely successful attempt at EQ'ing the car using an iPad + HouseCurve + microphone, a Pixel 6 Pro + Neutron Player, and a Tunai Firefly LDAC (the sound quaility is sooooo much better), the next step is to look at speaker replacement. I am much happier than I was, but now...

Hello I have an audio 20 system and was thinking of getting a slim sub like the GTB 200a actvie sub from Blaupunkt or the Pioneer TS-WX110A Underseat Compact Active Subwoofer (7 - 8 CM max height ) Would these fit under the front passnger car seat? could 2 be fitted one below each front...