If you haven't bought it yet that you could save some money and get an H series motherboard. The Z series is for overclocking so it's only worth getting if you get a -K CPU. In a corsair 300R the stock cooler on an 4690 will be fine, but as leeb said, it's going to be noisy under load and relatively hot. You might find that the CPU seems to slow down as the turbo boost feature is affected by heat, so if it starts getting too hot it's going to downclock. http://www.intel.com/support/processors/corei5/sb/CS-032278.htm
Update: that wasn't the link I thought it was, but it still notes that boost is affected by heat.
Yeah, i undervolted my xeon so it only draws 45w max, yet it still easily got to 65c with the stock cooler and the tiny fan is stupidly noisy. I quickly went back to the near silent evo212 and 50c max.