For those that are just extending the cable: How do you know your results are good and unaltered? I'll answer that for you: YOU DON'T!

The best advice I can give you, is learn how to properly adjust a system yourself.
I have NEVER used the built in calibration on receivers, they are never 100% accurate. They have gotten much better over the years but are still flawed, they will NOT get the adjustment 100% correct. There is always something that will be off on them, that has been my experience when I have tested them.
Go take the audio courses from THX and HAA, then get yourself some real test equipment and enjoy an eye opening experience of actually 'calibrating' an audio system.