Update and keep old bootloader topic

I'm currently on 4.3 with the original bootloader. Is it possible to update to an official touchwiz 4.4 or 5.0 rom and keep the old bootloader?
If no, are there any touchwiz roms modified to work with the old bootloader?
Does CM12 work well with the 4.3 bootloader?

Edit: I have the n9005 (n900x LDU to be exact) version of the Note 3.