All things come at a cost, so desiring both insane speed and insane battery life might not be possible... But, if you're looking for a lot of speed and decent battery life, here's what I've done:
1. Download and nstall the most recent 'codefireXperiment nightlies', which you can find here: http://downloads.codefi.re/synergy/c.../nightlies/mr2
. (Y'know the whole shebang, GAPPS are to be downloaded/installed as well)
2. Download and install the latest Faux123 kernel for JSS. Look at his first post for battery saving settings that you can use with Trickster Mod.
3. Download and install an app called Greenify from the Play Store + download and install either FauxClock or Trickster Mod from the Play Store.