[airspirit]

That is going to be one loud sonuvabitch. Get rid of the BIMs, first off. They are absolutely unnecessary. If you want to go strictly parallel, just use one pump (rather than the two you would need in that setup) and break off into two parallel loops. One would go to the CPU (think 1/2" ID tubing), and one would go to the GPU/HDDs (think 3/8" ID tubing). Hook the most efficient rad to the CPU, and the least efficient to the others.

Reconsider watercooling your HDDs. There is almost no point to it, really. You'd be better off directing a low speed and low voltage 120mm fan over them. Otherwise they will just provide an extra heat load to your watercooling loop. Just a thought.

Now, with all of that said, you will have a few things to overcome. You will need to find a way to do away with all of the air you will be pumping into the case through your rads. If you think one 80mm fan will do it, you have another thing coming. If you were to use Panaflo "L" 120mm fans on the rads at 7V pushing into the case, you would need a couple/few of the same pushing out to prevent air stagnation inside of the case (there is a good article on this here on procooling). With the amount of large fans you will be using, I would suggest something a little unconventional here:

USE THE FANS TO BLOW OUT OF THE CASE.

While the air that will blow over the rads will be warmer than the fresh external air, your system would be much quieter since you will be using half as many fans, and since you will be using three 120s, you will have enough flow through your case that the temperature difference will not be all that great. This, incidentally, would also help keep your HDDs from getting too warmed even if they are not watercooled. You will have to ensure that you have ample intake space in the back of your case (and your PSU, which will also benefit), and it would work great.

Anyway, those are my thoughts ....