BUILDING THE SYSTEM
As always the purpose of this section is not to build a functional system but rather to showcase what you can expect from the case at hand in terms of interior space.
The COUGAR MX500 is compatible with mATX and ATX mainboards but it seems that you may also be able to fit an EATX mainboard inside (just as long as it uses 7 PCI expansion slots).
You can probably use the largest CPU Cooler around and still have no issues with the top and rear of the tower.
If you choose to keep the HDD rack you will have up to 300mm of space for graphics cards but if you choose to remove it that goes to 410mm.
Using the longest power supply unit is no problem but you may have to forget using one of the two bottom holes for cable management.