You will barely notice the memory, as if you buy these and put them at 1600MHz as I have done:
Crucial Ballistix Sport DDR3 1333 PC3-10600 8GB 2x4GB CL9 BLS2CP4G3D1339DS1S00 DDR3 Memory
Editing:
http://xtremmedia.com/?q=cconfig/view#A003640,A001648,A022012,A001243,A008383,A017612
I would get that with the cheap 1333 memories and the rest of the parts that are not on that list at pccomponentes, about 370€ including shipping, in total less than 800.
Thank you very much!! Even better then!! I spend less on memory and if I can I can upgrade it elsewhere!!
Thanks again for the answer man!!