Theres a lot to be said about ordering from one place. Its worth a little extra to not have to pay multiple shipping charges and deal with multiple shipments/returns if necessary.
As to the memory, if you are running at auto settings you should be able to drop them down to 4-4-4-12. Not sure about the x48 board, but i know the p35 board you had to hit ctrl-f1 in the bios to get the memory settings to show up.
Heh, 224 isnt bad for a mobo. Look on newegg for how much my mobo cost