The thing you have to realise about the reserator is, that it isn't designed with super-cool temperatures in mind, it's designed for quitness, so i would definately not go down this road.
To be honest, you are trying to cool 2 of the hottest componants on the market at the moment, so you will want some pretty decent cooling, and, for this reason, i would not go for a kt, i would definately recommend getting a custom solution.
D-tek fuzion is regarded to be the best cpu block on the market for multi-stage cooling (ie more than just the cpu in the loop), but the swiftec apogee GTX is pretty much on a par, and even better in single stage loops. As for the GTX, you have to options really, the EK 88gtx full cover clock, or the danger den gtx full cover block. Reading around, there isn't much between these 2 blocks, other than price, the DD block is almost double the price of the EK block... a no brainer there really
(i opted for the EK, but the silly so and so's sent me a danger den block, i wont complain
)
If going for a single loop, then a thermochill PA 120.3 rad is an absolute must. As for the resevoir, then the bigger the better really i guess, as the more liquid that's in the loop, the longer it takes to heat up.
I would use a pretty decent pump, something along the lines of the D5 or a DDC, the faster you can pump the water around, the better, which brings me to tubing.. the thicker the better (although recent studies have stated that there is very little difference) but the fact that you will be dumping a whole lot of heat into the loop would make me choose the thicker tubing (better flow)
Alternatively you could opt for 2 loops, the pumps wouldn't need to be as powerful, the resevoirs not so big, and you should be able to get away with 2 smaller rads, But ultimately, this would cost a fair bit more, as you will be purchasing pretty much double of everything.
I myself have just decided to migrate to watercooling, i am going to be cooling my NB/CPU/GFX (680i/e6400/88gtx) in one loop using a 120.2 rad. I am probably going to be dumping too much heat into the loop for 1 120.2 rad, but im hoping that the faster pump, high flow barbs, and larger tubing will help me overcome this. I would like to upgrade to quad core soon, but i think that i may have to get a 120.3 rad to replace the current one before i even start to think of that
As for wanting a radbox... may i ask why? the case you have is huge, and should be able to accomodate water cooling rather easily...
EDIT: mostly beaten by matt there.. listen to him, he know's his stuff
