It's a very common air intake setup for the Mustang that works very well, which I'm still kinda involved in. I have an 85 GT project car that has had several different setups. Not to mention the 90 GT and 90 LX that I have played with that a close friend has.

Gotta get the filter out of the heat and into the fender where it can get the cooler air. Just not too low so that you play submarine when it rains.

Not saying that some of the stuff that replaces the stock air box and puts the filter next to the fender inlet is bad, but there is always a chance for heat soak.