need it? No, the stock cooler (while really small), works fairly well. The aftermarket cooler will be cooler and quieter. As noted above, you cannot OC much past the turbo boost setting on your CPU which is ~3.7GHz, which will not put out much more heat than the stock settings.
Try the stock cooler for a few days and see if you like it. If you find that it does not suit your needs then return the 212, if not then at least you have it and can give it a go.