Upgrading woofers in a/d/s L2030, need help

Hi folks, I have a pair of a/d/s L2030 speakers which have two 14" woofers in sealed enclosures. I am unaware of how many cu ft each driver is exposed to.
The drivers have a hexagonal shape.

I have owned a pair of infinity irs beta's in the past and loved the bass response. I am driving a bi-amp setup with one adcom 555 for the woofers both sides.

I am not getting enough bass out of the speakers, but I love the mids and highs, so I was thinking of upgrading the drivers.

I would create a plate out of metal to match the hexagonal shape of the original drivers, and then cut out an appropriate mounting circle.
I could get away with 13" or more standard 12" drivers.

As tacky as it seems, I may select a car audio driver that works well with sealed enclosures of various sizes. I had one of the 14" drivers replaced, and when it was out I noticed how puny the magnet was. And how today's voice coil structures and magnets seem infinitly larger.

Does anyone have any suggestions?

Thanks
Andrew