As for the pump they are the same pumps... that is the D5 that I would recommend...
The difference is that the one that is $10 more comes with a pump top the one without is expecting you to buy an aftermarket pump top. I would not recommend the one that comes with the pump top as they sell one for a few dollars more that has that same pump top but has been tapped to allow you to put fittings directly into it instead of hose over it. That allows you to run any hose size you want. If you have the money buy an aftermarket pump top and if it fits your needs buy a pump top that has a reservoir built into it. That may save you space, complexity, and cost of (2) fittings if you had a separate reservoir. Also nothing wrong with dual bay reservoirs but I have had situations where they rattle the case and the case ends up making noise so just a heads up. This is the modified pump top and pump if that is what you want to get http://www.frozencpu.com/products/18222/ex-pmp-231/Swiftech_MCP655-PWM-DRIVE_12v_Water_Pump_-_PWM_Enabled_w_G14_Thread_Ports_Perfectly_Tapped.html
This is a decent res top http://www.frozencpu.com/products/17572/ex-pmp-216/EK_D5_X-RES_Top_140_-_Acetal_-_Laing_D5_Swiftech_MCP655-B655655-PWM.html
But read about all the D5 res tops and be careful of poorly designed ones that could possibly allow air to be introduced into the water.
As for the radiator either of those radiators would be plenty... I have a Mo-Ra3 360 Core myself and I ended up putting it in the closet because it was overkill for me and I wanted the radiator to be in my case so I ended up with a black ice GTX 480 and GTS 120.
If you are going to have the radiator outside of the case you might as well go all out and get the larger of the 2 radiators. I have not read up on large radiators lately but there are plenty of people who have used the Mo-Ra 2 and 3 radiators in a passive mode. While I would always recommend you have some sort of fan on it since a really low RPM fan shouldn't bother you that decision is yours.
On my Mo-Ra I just used 2 180MM Silverstone air penetrators. They are not PWM though but with a huge radiator you could probably just set them to a really low manual speed and never worry about having to spool them up. They may have PWM versions but I don't know...
Anytime you have the chance to go PWM be it a fan or a pump go PWM... because even if you end up not using the PWM ability once you buy a non PWM fan or pump you can't go back. PWM fans/pumps can be controlled by PWM or normal fan controllers.
Anyways... look around the site there are a ton of people who have 39xx CPUs multiple GPUs and want silence! I am not saying you will end up doing this and that you are in anyway this type of person but a lot of people just end up throwing huge amounts of money at these builds and then end up being unhappy because it is loud.
It's a good thing you are planning ahead...
Also I would say you probably can't beat the value of a 120x9 / 4x180 radiator. A high end 360 or 480 usually costs around the same amount of money.
I did not know this when I bought my Mo-Ra and maybe they didn't have it at the time but they now have Mo-Ra 120x9 radiators that are designed to directly mount 4 180MM or 9 120MM fans or you can buy them designed to only mount 180MM or only mount 120MM and they sell stand/feet that are specifically designed for the Mo-Ra radiators.
These are the Mo-Ra products http://www.frozencpu.com/search.html?mv_profile=keyword_search&mv_session_id=WC3ePAdq&searchspec=mo-ra&go.x=8&go.y=23Edited by givmedew - 6/17/13 at 10:51pm