There is a root app called Viper4Android that I ran into somewhere around Xda.
It gives better sound quality & loudness than Stock Jellybean.
The sound it crisp & vibrant and totally better than the dolby.apk app.
This is not my work / app and all work goes to Viper520 & ZhuHang
And for all the lag just switch all animation scales to 0.5 in developer settings.
For the bad battery life just use the Greenify to hibernate those apps and you're good to go.
One more thing: Don't forget to smash my thanks button