Heres my thoughts.
People like you should stick to the stock kernels! Theres no way in hell anybody who breaks their device with overclocking should send it to warranty, for the following reasons:

1. If you break the device, you cant flash stock kernel back in.
2. At nokia service they will see that your using non-stock kernel and then figure out its an OC kernel one
2b. At which point they will just send the device back along with a propable bill for wasting their time with a device you broke yourself!
3. Its not right thing to do. Say I buy a new car, then I put in my own tuning fuels and oils, which make the car go faster for a moment but then engine breaks. Do you think it goes to warranty?

So there you have it. I didnt write the warranty void texts there just for fun! People... THINK before you flash any of these in your device.