why did you go with 3/8" tubing?
1/2" provides better performance with your pump.
Its not going to be a noticeable difference, and if i get round to building another water loop later on in life, i would probably go with 3/8" tubing, because it will be easier to work with in a smaller case, with no significant loss.
http://www.xtremesystems.org/forums/showthread.php?t=147767
6.35mm quick fit = 34.21C
8mm barbed = 34.08C
8mm quick fit = 33.91C
9.6mm barbed = 33.89C
9.6mm quick fit = 33.80C
11.1mm barbed = 33.79C
12.7mm barbed = 33.77C
Temperature wise, its not going to make a noticable difference
And flow wise, its also wont make a noticeable difference ( unless you use the extremely small tubing)
6.35mm quick fit = 4.45LPM flow, 0.0795 block c/w, 0.0374 rad c/w
8mm barbed = 4.75LPM, 0.0783 block c/w, 0.0373 rad c/w
8mm quick fit = 5.6LPM, 0.0770 block c/w, 0.0369 rad c/w
9.6mm barbed = 5.7LPM, 0.0768 block c/w, 0.0369 rad c/w
9.6mm quick fit = 6.2LPM, 0.0762 block c/w, 0.0367 rad c/w
11.1mm barbed = 6.3LPM, 0.0761 block c/w, 0.0367 rad c/w
12.7mm barbed = 6.35LPM, 0.0760 block c/w, 0.0366 rad c/w