When you have all of that hardware, more fans is a must. If you want a quiet system, combine those hard drives into one big one. That's going to remove most of the heat from your computer.PCI fans are ok, but I think you would do better by removing all of those hard drives.
On the other hand, if you can mod your system for a strong 120mm fan in the front and two 800mm fans in the rear or a strong 120mm fan in the rear, preferably with a throttle control. That would keep your case cool. Depending on your cables, you may even lower your case temps by 5 to 10 degrees by straigtening those out for maximum air flow.