Need advice on parts selection and purchasing

[Neutronium]

Thank you for your help ST.

But how should I go at purchasing those components? NCIX offers a service to assemble and test the parts for $50, but I can do that. The only worry is that I end up with a defective component and deal with RMA from across the country. Is that service worth it, or are defective components very rare with the selection I've chosen?