HD 7970 Temp in Counter Strike is over 70C

I don't own an HD 7970, nor do I play CS.

However, older games are often poorly optimized for newer hardware and it is very possible that CS and the HD 7970 drivers do not get along well.

I know that Neverwinter Nights 2 will run my CPUs (all of them) at 100% and run my GPU at 100% and I end up with 260+ FPS in the game, but still generate as much heat and noise as if I were playing BF3 on ultra settings.

Perhaps someone who owns an HD 7970 and CS can weigh in and give you a more definitive answer, but I'm willing to bet that it's an optimization issue and that it's "normal" although not necessarily desirable.

Other users report 83C at 53% fan speed in BF3 with the 7970, for what that's worth.

It's better to have your side panel closed, unless you have an additional fan blowing directly on components from the side, during a bench run or something.

This is because you need turbulent airflow to keep the "stagnant" spots in the case at bay and force turbulence to mix the air inside the case.

200mm intake and 3x120mm exhaust is fine, although you're at negative case pressure and you may be sucking air (and dust) in through unfiltered cracks or vents in the case. You might want to work on getting positive case pressure (having more intake than exhaust, by taking your back fan and turning it into an intake so that you have 200 and 120 intake with 2x 120 exhaust), that way you'll have positive case pressure and the dust will stay in your fan filters and not infiltrate through cracks.

You have more than enough case flow and have no reason to take your side panel off and add another fan externally unless you're crazy-benching.