Please help!

Can anyone advise me for the most latest & stable custom Rom for Xperia T3 D5103 with step by step guide.

If FXP Team is the answer, then which is the best one to consider "AOSP by FXP - Android 6.0 - AOSP_M_160717_seagull.zip" or "CM 12.1 by FXP - cm-12.1-20150715-UNOFFICIAL-seagull.zip" or other older versions.

Currently running stock Rom 4.4.4 build 18.1.A.2.25

Sorry, if my English is bad.
Positive & prompt reply will be appreciated.

Many Thanks