Yes. Just flash over your rom. Make sure you do a nandroid backup before you flash, incase you don't like it. For battery life, I'm still comparing it to not being over clocked. Also I'm using OC widget to minimize off screen usage. I'll let you guys know how it compares.
Does this fix the Tether issue I currently have with Fresh 2.1.2? It don't work right now and there is a fix for it that I still need to flash but if that fix is in this ZIP among the other things it does then I'll just Flash this one.