You have more than enough room to fit your dual D5 + top in your M8 + Pedestal, I think the problem you will have is NOT Knowing what to put inside, it has THAT much room.. I have a M10 + Pedestal, 4x 360 radiators, 25 fans, 2x RP452x2 and 4 D5, 2 PSU and a list of all the stuff that everyone else would have in a puter case... Its a bit crammed now.. 
With that note aside, The Alphacool res looks good, I don't own one.. but as previous poster mentioned, I much prefer to have a option to run serial or parallel on a single RP452 unit, with the Alphacool, it appears not to be an option..
I am curious as to how they manage the flow into the reservoir and back out, since it's a single reservoir and dual D5, A product review is all good but I really enjoy the actual testing and in depth info of a unit that Martin and Skineee provides, perhaps someone will post a review of the unit on here with similar info... (fingers crossed)..

With that note aside, The Alphacool res looks good, I don't own one.. but as previous poster mentioned, I much prefer to have a option to run serial or parallel on a single RP452 unit, with the Alphacool, it appears not to be an option..
I am curious as to how they manage the flow into the reservoir and back out, since it's a single reservoir and dual D5, A product review is all good but I really enjoy the actual testing and in depth info of a unit that Martin and Skineee provides, perhaps someone will post a review of the unit on here with similar info... (fingers crossed)..

























