While the design is simplistic, the case doesn't open in the classic manner of thumb-screws at the back, but instead uses a key-enabled push-back handle. It's not something impressive, but it serves to remind that P500 is not necessarily designed for the consumer-side of things.
Once inside, you get a modular design, with mediocre cable management. There are several zip-ties keeping some cables together, and even some plastic hooks at the bottom, but overall, when it comes to interior presentation, it once again, shows P500 has a different market in mind.
In the image below we have the 650W Platinum-Rated (92%) power supply from Lite-ON. You might notice it doesn't use a standard 24-pin ATX connection, which means whenever you intend to upgrade the machine, and might need a new PSU, you will have to go through Lenovo to get a more capable power-supply.
Next to it, are several tool-less plastic drive cages, with the Intel SSD screwed onto the top one. The SATA ports are positioned at the bottom, and are facing upward, which means the sticking cables will restrict access to the motherboard. Larger graphic cards positioned on the lower PCI-slots will essentially block the ports. This is why most MOBO makers place SATA ports at a right angle or further up the motherboard.
Lastly, the motherboard features 2x PCIe x16, 2x open-ended PCIe x4, 1x PCIe open-ended PCIe X1, and 1-flex Connector.
The added K2200 is an entry-level Quadro GPU, being priced at $599.00. Being a low-profile card, it doesn't eat a massive amount of space. This isn't the card offered in the basic P500 package, which is the Quadro K420 ($599 cheaper). The closest upgrade offered in the package is the K4200, for which you have to add about $400 to get.