I have a Biostar P43-A7 and have not overclocked it. I have changed the stock cooler and have CoolerMaster X Dream 4 (Which is again an air cooler but better performer than intel stock I guess) and further details are in this link. Cooler Master - Ultimate provider of Computer Chassis | Cooler | Power Supply I did not get the box with it but the one i brought had screws not the turn switch like in the link. What I want to ask is that if it is possible to overclock with this fan or I need something new to overclock.
It's always possible to overclock, even with a stock cooler. However, if you really want better cooling performance, look for a copper-based heatsink, especially stuff from Thermalright.