Hey Stang Man,
Welcome to ProCooling...
IMO you're asking for trouble mixing a water-cooled CPU block and a water-cooled TEC VGA block on the same loop. The TEC will dump a lot of heat into the water, which will raise your overall water temps - not good for the CPU block. Even at 80 watts the MCW50-T may compromise the water-cooling system performance for cooling the CPU. At least you have a big dual 120mm fan radiator which will help. Personally, I'd go two waterblocks or two water-cooled TECs (CPU and GPU). Good luck.