For the music distortion, use SetCPU (from the market) to bump up your MIN clock speed to 200 MHz.
As far as the best kernel, the Voodoo5 based kernels are by far the best IMHO. I would reccomend giving Adrynalyne's newly posted voodoo5 test kernels for DL09 that he just updated yesterday (in the dev section) a try. Great battery life, fixes from DL09 kernel, and Voodoo5. Winning combination.