It's very difficult to get a 1600+ to 2GHz at all, much less on air. Look at the heatsink rankings on the front page. If you want the best air cooling, get a SLK-800 and a tornado 84cfm fan. Still, you'll need low ambient temps and massive vcore. If you want cheaper, get a SK-7 or an AX-7.
I've had a CAK38 with a delta38 on it. It's an OK heatsink, but not the best. However, when I upgraded from the CAK to an AX-7 with delta68, I couldn't stand the noise. It finally got to me and I switched to watercooling. I HIGHLY suggest you listen to some of these fans before you buy. It might change your mind.
i have 7 fans already, case is always open, my comp sounds like a factory, noise is not an issue, as im usually drowning it out with music or games i can hit nearly 1800mhz on my crappy standard coolermaster heatsink, so i was hoping to hit 2 ghz with a good heatsink..