I would like to know if this kit would be good enough to add a Sapphire HD 6950(flashed to 6970) to the loop with a FX 8120? I am really happy with the performance of the kit with the CPU it is running 29c idle/surfing and full load running Prime95 only went up to 35c after 5 or so hours. With the stock cooler it was running 40c idle.
No. You'd need at least the RS360 to do that; RX360 would give you better results yet. You also need to consider the waterblock for the GPU, fittings and tubing (unless you have enough left over from the Rasa kit). Also, Rasa kits are typically 7/16"ID (I believe) tubing size, make sure you take this into consideration when choosing fittings for your extra blocks.