My system is made up of Swiftech, Rads, Water Blocks, and Pump. The restriction of the two rads and three blocks combined with 3/8" tubing is not a problem. I still get good flow rates. I put my rads in parallel because Swftech recommends it for better heat dissipation witch leads to better temps. I have also read reviews of the Swiftech setup which confirm the temp drops of a parallel configuration.
I like stryders setup. However he might gain even beter temps with a parallel setup though. But if he's satisfied with the way it is then hey, thats his right, right?