The noctua cooler is inferior to most of the other large tower coolers out there. Grab a Prolimatech megahalems, megashadow, or a TRUE. Also the x58 platform uses triple channel ram so you should grab a 3 x 2GB kit.
Yes, they typically can reach higher clocks at lower voltages that the original C0 steppings. If you buy from newegg, chances are that you'll get a D0. If you go to a B&M store you'll wanna look at the box. It should say "S spec: SLEBJ". Microcenter has the 920 for $200, so if you have one even remotely close to you, I recommend that you take advantage of it.