So much of this depends on PC case airflow. All the fans in the world won't help if the hot spot is in a dead zone regardless of how much air flow there might be. Check the exhaust air and if it is not really really hot with high GPU/CPU temps then that heat is building up in the case. As these rigs require more power and the PSU wattage gets higher then cooling efficiency is going to be increasingly important.
I can recommend Falcon Northwest. Roughly as pricey as Alienware or Jetline but top notch quality and support. Their builds are as elegant as any premade PC I have ever seen. You really don't need data drives anymore. One decent sized M.2 SSD stick is plenty. Gone are the days where you needed to get more spindles for performance.