Looks like a very clean job Laz.
Clever use of the split water stream to cool the motherboard chip and the video chip.
The one conscern I would have is your air-trap. Note: I am not an expert, I've just done a lot of reading in last couple of days. (I've got the bug too and my WBs should be here next wednesday)
I'm sure you flushed your system of air (tapped the radiator and twisted it) to bleed off air trapped inside. I hear that radiators are great a trapping air.
Most Important: All systems will get air in them and that air will rise to the highest level in the system.
Laz, in your system the highest point is the radiator. This could prevent liquid from contacting the radiator surface and limit cooling. The "T" connector you have in your 'old' system will probably not act as a very effective air bleed; the air may just rip right past to opening (it has happened before).
Some more experienced people might have better insight into this. Perhaps you could move the reservoir to the top, cut a hole to let it stickout the top (add LEDs for colored water effect) and plumb it in series with the radiator.
Then again, if that is 3/8" Inner Diameter tubing, it may be slowing your flow down enough to capture some or most of the air. Like I said, I'm no expert.
Also your 'old' system looks like you could experiment with reversing the flow through the cpu water block to see if it cools any differently...
Happy water coooooling...
mh