Kernel updater is just a script that downloads the latest 3.16 kernel, it will downlaod the latest one that may or may not have been available for your system yet. It also may or may not break things on your system
not at all. i love kernel updates. i remember back in 2009 when i did my first i was so in full panic because, knowing windows, i feared i would end up with a complete broken system in case anything goes wrong.
it worked but i did not know why. and i was just happy.
got my htc desire and that was running on android and android is also just a linux sys.
i replaced my iphone 3g with an android device because i knew from xda-developers that you could heavily modify it and also run custom kernels.
only thanks to android i learnt that a kernel is not an os. it's 2 different things. and i love the way linux/android handles it.
if i install a kernel not suiting my needs, i still can boot the previous one.
a kernel update with my update tool or manually or via update manager N E V E R deletes the old kernel.
the worst thing can happen is your os won't boot, you press the reset button next time you get a boot menu you chose the previous kernel to boot, then you uninstall the new one. mission accomplished.
kernel updates these days or even in previous days are a bit like bios updates these days. these days even if you screw up your bios update, the bios itself (!) detects it and flashed back the old one.
this was not the norm 14 years back when i first destroyed one mainboard through a wrong bios flash, thankfully the nice guy in my pc store could flash it back.