Hi everyone, I recently got an 05 Mazda3 Hatch and was wondering if anyone has any suggestions on how I can (at an affordable price) play mp3 via mp3 player or cd/dvd player? Also, with regards to speakers, will upgrading my stock speakers be worth it or will simply adding tweeters in front be fine? Then again, is it better to have a sub and separate speakers installed instead?

If you know any good shops that provide good services to Mazda3 at affordable prices, could you please let me know their locations and contact numbers? Super newbie with car stuff. Thank you in advance!!!