You can bench test it by installing it into your PC as if you're going to run it (but no thermal compound), then just pull off the blocks and lay them out the side of the case. But this isn't a perfect situation as you can't catch all the leaks if you actually have one. Not all leaks happen at fittings...
It's worth the time spent to install it as you're going to run it (to get the tube lengths right, then not disconnect) and pull it all out again. One night and maybe an hour's worth of work...I wouldn't skimp on the precautions! I trust my work more than I should, and should follow my own advise, but I still leave the rad in there during the initial run. Everything else get's slung out the side.
Loop configs mean nothing. There's a thread where Fallguy and I discussed it's long and short-commings...but the results still show that there's no more than a couple degrees difference when routing. It's better to lay out the route for shorter tubing and less restrictions as these two have more affect on cooling than a simple path re-route would do.
The silver TDX isn't worth the way higher cost. They do perform the same, and you can't see the silver so aesthetics can be ruled out.
Watch the lexan reservoirs that have plugs behind the mounting holes, they can leak at some point. DD used to have some, but from the pics on their site
, but their floppy bay res looks like it has plugs now too. Not sure...see if IamDaMan pops up with his take.
The radiator is a nice value I suppose. The BIX would be a better choice IMO, but doesn't have a shroud (and don't feel it needs one) and cost $10 more. The BIX comes with plastic barbs, which I didn't use at all as I prefer stainless or anodized hardware. Anyway, that rad is $54, and doesn't seem like it'll hurt anything.
Aaaaand, the pump. Swiftech has a newer pump at the same price that you may like. It's a Delphi electronics pump called the MCP350. The reviews look very promising...check it out. I think that little thing has better performance than my HPPS (except in the GpM area, which I need).