I installed kernel 3.1.2 from the stable standard repo http://download.opensuse.org/repositories/Kernel:/stable/standard/repo, rebooted and when compiling Nvidia drivers got a message that the gcc used to compile the kernel differed from the installed gcc and did I wish to continue as this might not be a good thing (or something similar as best as I can recall).
I then reverted back to the 12.1 shipped kernel and rebooted, seemed the smartest course of action
Questions:
- should not the stable standard Kernel be compiled using the shipped gcc?
- if I compiled the Nvidia drivers, with the gcc mismatched would this be a bad thing?
Yes, it would be a bad thing. I tried it, it didn’t work.
Unless you have a reason for needing a newer kernel than the one provided in the default install, I really don’t recommend it. Even then, you might want to try Tumbleweed instead (although even then, there is no guarantee that you won’t have issues with proprietary drivers such as NVidia).
Instead of the ‘stable’ which was set up for 11.4 you could try the ‘12.1’ (the folder within the Kernel: repo you mention) which had a newer 3.1.x kernel last time I looked.
Thank you for the additional information, peteh100. While I don’t completely retract my previous comment, I’m not quite as convinced of my initial position. Its still not something for new or non-techie users, but perhaps not as fraught as I initially feared. 
It’s not rocket science, so if you think a newer kernel will give you something extra (even if you’re not sure what) then it’s fairly easy to do from a repo.
Now,compiling your own - that’s different!