In that airspace you could go ported with th Si SQL 12@$369, hands down the best option in a 1.41 ported box. With 1000 watts RMS and 92 db efficiency, tuned to around 25-30hz, as your Vb will be around 1.25 cubic feet
https://stereointegrity.com/product/sql-12-series-2/
Another REALLY good...