Honestly Liquid coolers are not as great as they sound, there is a lot more hype than use to them. You would need to really know the benefits of having one rather than just having one. You have a 4 Physical core CPU, it will emit heat upon use of those four cores, in this situation, a good air cooler has more than enough capability to keep your CPU running at good temps. If we were talking about the new gen 6physical core CPUs, we would move the price/performance scale quite a bit higher, because those 6 cores create a lot more heat.
I would suggest to invest straight away into a liquid cooler (if you wish to have one), they work fine with age, I've had mine for 6 years running my CPU at 4.7Ghz (3.4ghz stock). But the Air Coolers are...