Project Cars is still in alpha/beta, hard to say what the final requirements will be. Just for comparison, Assetto Corsa in alpha with 17 AI cars gave me 30 FPS, release candidate 1 gives me 70-140 fps, depending on quality settings.
AMD fx-8350, gtx 760, 12 gig 1600 mhz ram.
His proposed system is much better than what I have.