We have two coolers on our X.. We have them stacked in front of each other and run in series.
In our case we have a transcooler with a fan in front (about 10" across, 12" tall).. Behind that we have another cooler that is about 12" tall but over 20" across.. Behind that is the a/c condensor.. behind that is the radiator..
The transmission does seem to run a little cooler, but only while moving. I think with all those things stacked on top of each other that I'm blocking too much air.
At idle, even with the aux fan in front of the cooler running the temp of the truck (water) will slowly rise until it just about overheats. I don't remember having that issue when I had the single smallish cooler up front (no fan, and no 2nd cooler)
My plan now is to remove the two coolers I currently have and get one plate cooler that is still only 10" across (so it only covers 1/2 of the condensor) but that is tall enough to give me more surface area and keep the fan on the front of it to help around town.
~Mark