Honestly, new speakers won't do a whole lot for you I wouldn't think. New speakers would have a little better sound quality, but they would be underpowered by the headunit. If you throw an amp in there with some new speakers, then you'll get some good sound. I'm not sure how the Bose tweeters are wired, but to get them to stay working, you will more than likely need a crossover. You could just get component speakers that come with a new tweeter.