The one thing I would also point out in terms of the 18 month warranty of the TM plan is that the individual parts themselves will have a longer warranty on them, in the case of HDDs, that's 3-5 years depending on the manufacturer.
I had to send back a faulty GPU when I built my system, all got handled fine.
Nice machine! If you asked Revo to put the items together in the forum, he will be able to give specials for you. I think you will need good power supply and should be at least 650 watt to overclock. Good luck.