[pHaestus]

It's really going to depend on what motherboard you use (CPU temps vary pretty widely depending upon mobo model and even BIOS), the temperature of the air going into the rad (if it's cooled via exhausting case air then it could be 5C warmer than the room easily). I'd say it's probably possible because my S939 A64 stays below 50C with stock cooling, and it's overclocked a good bit (2.5GHz) and overvolted a good bit (1.65V).

The 10mm id tubing isn't that big a deal as long as you are using only the push in fittings to connect everything up. If you are using hosebarbs though then they will be closer to 7mm id and will be a pretty big restriction.

I don't care for the L30 too much; mine started a rattling (like it had gravel in it) about 2 months after I installed it. The L30 isn't a particularly high pressure pump and so it will be negatively-affected from using smaller ID tubing somewhat more than some of the newer pumps (the 50Z, MCP350, or MCP650). It should work though.

I would expect the Asetek antarctica to perform similarly to the DTek WW or the Dangerden RBX: Relatively big improvements for increasing flow rate from 0.25 to 1GPM or so and then diminishing returns. You'll want to get "above that knee" and then it doesn't matter much.