This is a Perma-Cool Model 1200 Heavy Duty Two-Pass Power Steering Fluid Cooler.  You can buy them from Summit Racing Equipment (they aren't listed in the catalog but can get them if you call and ask).

If you plan to take your 4th Gen F-Body to a roadcourse, you will boil your PS fluid sooner or later.  You need a cooler.

I originally installed a "Frame Rail Tranny Cooler," also from Perma-Cool.  I didn't have much luck with it.  Mounted the way many have done before, you can see it won't get much airflow accross it:

Although I think this is more a matter of contributing factors adding up than pure failure of the cooler itself (driving faster than before, dry track, warm weather, no Red Line fluid, etc)  the next event I attended after adding this cooler burned out my PS pump.  This is what my fluid looked like afterward:

No, it isn't supposed to be that color.

I mounted the cooler in the open spot of the fan shroud shown here:

The airflow it recieves will be a bit warmer than ambient, but at least it has airflow.  PS fluid temp is pretty low on my list of priorities.  Keep it from boiling and puking all over the place, make the pump last and it's good enough.  A cooler mounted in front of the radiator would certainly be more effective at cooling the PS fluid, but it would reduce the efficiency of the radiator for keeping the engine cool.  I consider the latter a higher priority than the former.

Since installing this cooler I have had no problems.  It gets the job done.