You've confirmed that the noise goes away when you switch to "Econ" or turn the climate control off? If so, I'd say you can try to get out in front of the repair - or just let it crater and deal with it when the inevitable comes. I guess there's an argument that chunks of the failed compressor could clog other parts of the system and cause a more costly repair ultimately. The compressor on my wife's G got a little noisy, but not too bad. A friend's '05 G is also making noise... Ours made it to almost 170K with no issues though. If it were me, I'd let it ride unless you just can't stand the noise.