Just did system update and forgot I had TWRP and root and now the updates changes havent taken affect!
The best way to 4.3 may be unrooting and flashing the stock recovery image.

I used the Nexus Root Toolkit 1.6.4 to install 4.3 on a Galaxy Nexus having some minor problems. I would suggest waiting for NRT 1.6.6 which will have full support for 4.3