Advice on improving sound of 8 speaker stock Bose system?

[lreinstein]

Hi everyone. I just bought a 2008 M35x and I would like to upgrade the sound system if possible. I have no experience so any and all advice is welcome. Obviously I do not want to replace the head. I mostly listen to Jazz and Classical so am not interested in big base sound. I am mainly interested in clarity, presence etc. (My former cheap honda accord system sounded better..perhaps due to in-dash tweeters). I also would like to do as little as possible to mess up the electronics to improve things. Another main goal would be to be able to hear the bluetooth phone calls I get more clearly (with hindsight I probably should have gone for the advanced tech package with speakers near my ears in the seat). I think tweeters would help here. 1. So, what should I try first. Would simple door speaker upgrades help me accomplish this? 2. Are there replacement upgrades for the dashboard speakers (I did not see any on crutchfield site).? 3. Can I get tweeters installed relatively easily given available holes? 4. How important is a new amplifier? And for that, it would mean a digital processor etc I assume? this would all take up extra real estate which is pretty limited in the M35.

ADDITIONAL QUESTIONS:

5. What are the specs of this standard Bose speakers? What kind/watts of amplifier and what kind of speakers? Thank you Thank you. Larry