[Long Haired Git]

Cathar has found that using 7/16ths tubing gives you the flexibility of 3/8" tubing with the same flow rate as 1/2" tubing. Seems stretching it over the barbs eases the flow on entry to the barb and balances the slightly extract restriction over the length of the tubing. Otherwise, go the 3/8" as its only with like 7LPM or more that you'll see any real impact. 1/2" tubing is from the days where we tried to use mega flow rates to get performance out of simplistic blocks.

I'd go the eheim 1048 and revel in the silence. However, MCP350 is a good second choice. Performance difference between MCP350 and 655 is often less than one degree, but the MCP350 is smaller, quieter and draws less power.

If you care not for performance that much, go the Apogee. Its less restrictive and thus you can run a "gentler" and hence less noisy pump. Its also cheaper. If you want that last degree or two, have a dense core (no big IHS) then go the twice-as-much Storm.

Similar for silence and performance, I'd go a QP series or PA series radiators.

T line versus reservoir? Your choice. No real difference. Filling and bleeding are annual activities. If you are going to pimp the rig up, go the reservoir with LEDs etc.