After over two years in production, the Antec P180 and its derivatives remain extremely popular not only among PC silencers but PC enthusiasts everywhere. Despite its many strengths, one criticism has been that air inflow could be better, especially when the front door is closed. This is an issue that has become more evident as gaming video cards increased in power & heat. There are several threads here in the forums where comments about the need for more air inflow has been loudly noted.
The primary bottleneck is a fairly minor one: It's the hinged doors that cover the intake vents behind the main front door. These doors (there are 2) are designed like angled venetian blinds, but with one major difference, which is the flaw: Rather than being of constant thickness, the front edge of each slat is quite thin but considerably thicker on the back side. This makes the cross section profile of each slat a sharp triangle, if you can picture what I mean.
The photos of the intake covers below help to illustrate what I'm saying.


When presented with these covers while working on the prototype design, I expressed concern about potential airflow restriction; the slat design was not exactly what I had intended. Antec did not wish to incur the cost of retooling the mold for the part, which is apparently quite expensive. (At this point, they had no idea just how successul the P180 would be...) Also, real system testing at that stage showed that the case had no problems with cooling the hottest components around at this time.... which was pre-SLI. So, the grill was left unchanged.
Flash forward 3 years. Dual vidcard gaming machines are commonplace, as are 150W GPUs. The biggest issue with the P180/182 is cooling of high power video cards without incurring more noise. There are many simple solutions for just cooling alone -- but cooling without additional noise is more of a challenge.
Here's the simplest way to improve the airflow in a P180/182/190 without adding more noise:
Remove the cover grill doors for the front intake vents. Just push down a bit on a small tension tab near the top pin hinge and the plastic cover grill will slip off easily. This will drop overall temperatures in most systems. By how much is difficult to say, it depends on the details, but I'd guess at least a couple of degrees overall for most systems, and probably more for very hot ones. You could also remove the dust filters as well for a bit more improvement, but that will leave the metal visible whenever you open the door -- which might not be an issue if you leave it closed most of the time and wish to have the highest airflow. With the filters on, the black face is still mostly uninterrupted -- you can easily paint the metal that's exposed.
The metal grill behind the dust filters present much less restriction; the metal only covers 10-15% of the total area. Removing the metail grill is something diehard modders will still want to do. If you do, take care not to cut the holes for the filter clip and note that there's more of a chance of EMI when the aluminum door is open.
Note that the grill all around the sides, top and bottom of the front bezel/door is quite open and provides very good airflow access when the front door is closed. Still, opening the door after the vent covers are removed may give a bit more airflow improvement, but at the cost of more direct path for sound between user and the noise producing components inside the computer.
FYI, Antec finally agreed recently to replace the vent covers for a more open design. It's not clear exactly when this change will occur in the production line, but I'd guess that it will not be a major announcement, just a running change on the next run after the new cover is ready. I'm also not sure exactly what the new cover design will be, just that it'll be much more open. (I'm not involved in the current evolution of the case and was not involved at all in the P190 design.) I've asked Antec to make the new cover available for existing P180/182/190 owners to retrofit if they wish; it probably won't be free, but I expect it'll be quite reasonable.