Question [Q] Updating firmware version on UL bootloader or simply flash new rom

Hi guys,i have an xperia z1 and i unlocked the bootloader and i am running the AOSB project ROM on my phone, but when i installed that ROM the firmware version the newest one was the 14.2.A.1.136 and i used the NUT thread and links, so i got the double recovery, and the i wiped everything installed the rom and gapps and everything is working fine except that i lost TWRP and only have CWM as of right now. My question is should i update my firmware to the newest one following NUT threads up to 14.3.A.0.757 and then install the new PAC rom or since i have UB just fastboot kernel, reset, flash rom and gapps ? Will anything change if i install newest firmware. And can i install NUT firmware with recovery and SU even though i am on UB? Any help is appreciated.