Upgrade Mac Pro 5.2 2012 I have a Mac Pro 5.2 2012 which currently has both the GeForce and Radeon, 16 GB memory and 1TB normal HDD. I want to upgrade this Mac Pro to its max without over doing something, for example I read in some articles that upgrading it to 96GB memory will give the same result if having 128GB meaning the extra memory is kinda useless. I also read that the bluetooth needs to be changed to support things. So can anyone advise me with the best configurations for Harddrive, memory, GPUs, bluetooth and USB ports?
"to its max" is extremely vague, especially as you didn't really tell us much about your existing configuration.

But here are some 'max' specs you can run on a 2012 Pro


Max RAM - 128GB in dual channel or 96GB in triple channel.  ~$400 (but only if you have a dual CPU) - [OWC]
Max Graphics - Nvidia GTX Titan X or AMD RX 5700 - [macvidcards] $675 - $800 
Max OS - generally High Sierra with NVidia or Mojave with AMD.  
Max Drives - 7. Four in the regular bays, one above the optical &amp; two on a PCI card - [Mac Pro PCIe SSD Hardware Options]  
Max CPUs - dual 6-core Xeon 3.46GHz - [OWC] $1,379
Max Bluetooth/WiFi - [macvidcards] $175
Max USB - 4-port PCI USB 3 card - [innatek] $30 (but many of these type of card are incompatible with newer OSes 10.10+))