Unhappy [Q] GAPPS screw up my s4

Hi,

i have serious problems with my S4(i9505):

I rooted it when i got it and have installed various roms so far. The last working one was "liquid smooth".

Then it begann to reboot from time to time and when the problems got worse i decided to reinstall again... now, i think my problems arrived with the 4.4 roms. I installed pacman and tried to boot, it didn't work and i think that's when my bootup sequence changed, now i have a little text in the corner saying "kernel is not seandroid enforcing. Set warranty bit : kernel"
so i thought something must be wrong with the kernel and installed various kernels, hoping to clear that message in the corner. At some point i realized that this only makes my situation worse (s4 reboots directly after booting, while bootin, while finishing up "first boot", it gets stuck in bootloops, etc).
Right now i'm not even sure if i understand the whole concept of kernels and roms anymore... so i decided to ignore the message for now and focus on getting my phone to work... i installed some roms again, some (i think the 4.2'S) seem to work, the 4.3's all crash while booting...
i managed to get liquid smooth back on it again (2.9).
Oh and i tried reinstalling stock kernel but the installation under CWM aborted.

Now i can use basic phone options again, but as soon as i flash gapps(no matter on which rom (Cyanogen, pacman, liquid smooth), the phone won't boot anymore, i re-downloaded the package several times, it's the latest one, so it should be okay...
S4 google edition of course doesn't work at all ...
Anyone an idea, how i can get google apps back ? Or basically just get my phone to work ?

Furthermore : How do i clear the message (kernel is not seandroid enforcing)? My basic goal is to have a working android 4.3 enviroment with gapps...can't be that hard ...

i spent the whole day on that, i have used searchfunction not only on this forum, so sorry if i have missed a thread stating the same problem. Plus: i need someone to talk to

EDIT:
I've installed Stock ROM, now it keeps rebooting at the point where i can set up wlan ...