You can overclock your cpu in all build listed in this post until now, including mine.
Overclocking is free performance. There is no reason not to overclock. It is completely safe as long as you don't dial in ridiculous values or going for very aggressive overclocking.
Only thing is the temperature increases as you overclock more. That's why we use good coolers. The cooler i listed is a very good one, top tier. Also the case i listed includes two case fans. Add two more and you will have very good low temperature.