Adding Extra Cooling to Gigabyte z68ap-d3

I own a gigabyte z68ap-d3 motherboard. I believe that the board it self has sufficient stock cooling heat sinks.

My last motherboard's south bridge had burned do to overheating and this time I am a bit more cautions about my overclocking.

So my question, and hopefully some of you understand this better than I do, would it help if I was to add additional 'Heat Sinks' to my motherboard for more sufficient cooling and long term longevity?

I have attached some photos where I am thinking of adding these sinks.. let me know your opinion and expertise please