All except the GPU is fine on that system. Here what I recommend:
-any 2.0Ghz+ Quadcore CPU is fine (Intel or AMD doesn't matter)
-4GB RAM since it's so cheap (might as well get 8GB)
-a fast HDD or even SSD (also reduces start up time for windows) RAID will not help much because the stuttering is mostly caused by the seek-time
-for GPU it's a bit tricky 'cause this game doesn't like some GPUs for whatever reason. You will definately need highend for highest settings though. So for AMD something that ends with 850 or 870 (e.g. HD7850) and for nvidia something that ends with 60 or 70 (e.g. GTX 560). Personally I'd buy a HD7850 since it brings new features and has lots of power per watt but the drivers might cause problems at first. And don't rely on SLI or Crossfire for this game... very buggy.