I got mad for the bass i went top of the range with JL audio 2x 12" twin in the boot. I no longer have a boot 😂 puts out some bass tho does weight 30kg in total but I don't mind the weight best bet is a sub and amp serpents a lot more work but in my opinion looks better I fitted my amp under passenger seat, easy to wire up throught the door skirts or you can get a sub with built in amp few mates have these still pretty decent gives a good kick good makes are like JL audio, Rockford, alpine, kenwood, infinity, I wouldn't recommend getting cheap vibe or fussion one no good in my opinion and for head unit don't need anything special I got sony one £100 with aux USB Bluetooth depends what perks you want with it just be sure it has at least one pre-out put And good watts out put mines 4x52 watts but can't turn it up full, to power ful for my front speakers which are 4" alpines 👍