I decided to keep my 2004 mini and upgrade the sound after driving a 2021 with a harman kardon system around for two weeks. awesome sound

what system would you recommend?

 

I recommend a Milltek.

 

I'm working on a 2 Din conversion kit and should have some prototypes soon. Message me. The plan will be that it will come with the 2din adapter, stereo harness, and new (non-painted) columns to complete a fairly moderate install without a lot of cutting or time.