Which rom & kernel?

Hi. I just upgraded from Z3 compact to N5X. I was really satisfied with my Z3c, but I wanted a change. Now I'm trying to figure out which rom and kernel I should choose? Any recommendation? Priorities is battery life and performance (I'm not playing any games tho)

Also, should I flash the rom first and then the kernel afterwards?

Thanks a lot

from xda-developers http://ift.tt/1MWgsaJ
via IFTTT