Subwoofer for Mini Cooper Convertible BJ. 2005

Hello, I’m looking for a subwoofer for my MINI Cooper Convertible (TSN: 0005, HSN: 801 BJ: 2005). It should be noted that the trunk is largely separated and there is only little space available. Would an active underseat subwoofer be recommended? Have only a cheap Renegade passive subwoofer installed in an old Ford Fiesta, but was quite satisfied because the bass was actually really good – the car was also quite small. The goal is a strong, “ordinary” bass – should b the size of the car is actually not all too difficult / expensive to reach – the old loudspeakers should be used further. At the price I would like to remain as low as possible, but still not buy absolute scrap. A housing subwoofer does not seem to make much sense, because the trunk is too small and is relatively separated from the driver’s cabin. It should be noted that the car belongs to my parents (in the evening students without income) and I completely use it It must be possible to undo everything without damage. Thank you in advance! Greetings, Nestade EDIT: I think this belongs in the Car Audio & Navigation Forum – please move if necessary! Sorry!