xspc stuff is ok, some stuff is good but other stuff is rubish!!!
they have a decent midrange radiator, good acrylic top for ther laing ddc pumps but i wouldnt touch them for there water blocks-no way!!!!
Actually the higher end radiator(RX) competes directly with the feser and thermochill models while the RS series are midrange. Their tops for the Laing DDC are unparalleled however.
Waterblocks:
I personally run a midrange block, the apogee GTZ which is an excellent block for the price. Another good block is the Dtek Fuzion V2, but i personally prefer the GTZ as it has a great finish and good flow rate.
Pump/Res:
I highly recommend the XSPC Resorvoir Top for the MCP355/Laing DDC, it has been tested multiple times to have the best flow rate of any top, eliminates the need for a seperate resorvoir as well(less fittings to deal with, less tubing in the loop, more flow as well)
Radiator:
Most hassle free way to mount a rad in that case would be getting an RX240, Thermochill PA 120.2, or Feser 240.
Fittings:
Cheaper than compressions, barbs are usually the way to go on a budget setup. Bitspower or Dangerden Fatboy barbs have the best flow rate of barbs for 1/2"
Tubing:
Tygon, Feser, Or Clearflex 60 for tubing, and get 1/2" ID by 3/4" OD.
Fans:
Honestly 120x38mm will give you the best results, however most are louder than 120x25mm fans. For 120x25mm fans i recommend the Coolermaster R4's, thats what i run and have decent results. For better cooling though, the medium speed ultra kaze, or the 120x38mm SilenX fans work pretty well.(SilenX fans are pretty pricey though)