This is the setup from my e30 wagon. I didn’t want a ton of weight and I wanted great power/sound. This setup bumped extremely well, and was minimal relatively speaking.
Kicker L7 Solobaric 10" subwoofer, dual 2 ohm voice coils $100
Carpeted box with grill $40
or
custom box to fit in e30 BMW spare tire well and fill proper depth $80
Orion Xtreme 300 amplifier, ran it bridged mono and it was MORE than enough power $100
Everything was purchased new by me, no hot stuff.
text/call 716 7two5-5three66