So the TLDR for this answer is:
YES SLI 2X470 is fine with 750W PSU BUT NO OC?
A follow up question. How much of a heat increase inside my case can I expect? Would it be advisable to ad 1 or 2 more fans to improve cooling? Or would a dedicated GPU cooler be a better/safer way to go?
Thinking of getting a second GTX 470 for an SLI setup but I am concerned about the amount of power I might need.
I have utilized the eXtreme power supply calculator to the best of my ability and it shows that with my current desktop setup I should run @ ~650 watts required with a 2X470 SLI...