Don't worry, Speedfan's Aux. Temperature sensor @ 122C is a known bug. Use Coretemp instead, the latest version shows all 4 cores:
Core Temp. Have you tried 1.45V? If your temps are still below 60C under load (any core), you still good to go! NB volts are used to stabilise both high-FSB oc'ing and Ram (especially 4x1Gb sticks).
Water-cooling is not really difficult. Ity may help you reach a higher FSB, but not that much. Air cooling is very efficient; water-cooling will help you when a chip is running really hot, when you want to bench at very high VCore and when you wish to lower the noise generated by an Air cooler. The water-cooling fans are usually quieter.
I still think you have one heck of a chip in your hands, and you're not missing much to reach your goal.