Default Mixing AOSP sources with Galaxy S4 Team-Gummy code

Hi all,
I've been experiencing with Team-Gummy Rom source code for quite some time now. I usually compile from source to get the latest, along with some of my own addition. Lately I've been obsessed with having Android L code running on my Galaxy S4 (qcom) and so I downloaded AOSP source and after some failed attempts I was able to build it with the S4 device package from Team gummy.

So way cool! I may have in my hands the first (maybe not but as far as I know anyway) Android L build on the S4. But before going further, I have a question. In theory if I flash the system.img file produced by the build process and keep the kernel and boot.img from my current install, it should all come together right? Anyone here has an Idea what it would do?