New sound system for Polo 6R

Hello together! I’ve signed up here to get some help with a new sound system for my polo. I’ve tried the search before, but found nothing suitable for me. Unfortunately I was a bit too quick tonight and I posted the topic in another area, but my concern remains the same. At the moment I have the very normal system installed. However, I’m not really sure about the quality, especially bass is not available. h have no idea in this area and also my circle of friends is completely overwhelmed, I turn to you What I am looking for: – better sound quality – significantly more bass – jack connection to infect smartphones – price I can hardly estimate, in principle it can go higher (up to 600€), but I don’t know if this is really ‘higher’ and if I really have to spend so much to satisfy my needs I have no idea when installing it. if you still have questions, because my information is too inaccurate, then ask and I will answer as well as possible Already in advance thank you very much!