The front is very minimalist to say the least. With the door closed, there is really not much to look at here. The noise absorption foam will not allow for side fans or windows cut out, as that would defeat the purpose of what Cooler Master is trying to accomplish.
With the front door open, you can see the first glimpse of the noise absorption foam installed on the Silencio 450. The front I/O panel sports: one USB 3.0, one USB 2.0,
Mic, Audio, and an SD card reader.
The back of the Silencio 450 comes equipped with the basic default setup: one 120mm exhaust fan and two pre-cut holes for routing wires and tubing in and out of the case. Cooler Master did put ventilation holes on the other side of the PCI slots to help alleviate more excess hot air.