Id go for the 120.3 instead of running 2 rads, cleaner that way, actully one of the double HC's would be good as well, not as big as the tripple rads, but they do a fine job. Pump choice is tough, the MCP650 is not quiet to some, to me it is. I have no experience with the MCP350 but it claims to be very quiet. The aquaxtreme 50z is a good performing quietish pump, can be found at
www.cooltechica.com this is the same pump as the discontinued MCP600. I prefer 1/2" tubing, Cathar is hell bent on 7/16" tubing and some like 3/8" tubing. For max performance go with the 1/2".