I have this one sitting in my room, waiting to install as soon as I'm finished with finals. I've seen many people talking about it with great results.

It is best to mount it in front of the radiator and a/c condenser (if applicable) for best results. It won't make any difference in the efficiency of the radiator but if the aux trans cooler is mounted elsewhere, its efficiency drops as low as 40%.

My buddy is a mechanic and he told me to install it before the radiator. He said either side is fine. I installed mine on the passengers side.
I too live in Phoenix and although mine isnt a daily driver, I havent had any issues with my new cooler where it is both on where I mounted it and before the radiator cooler.
When I didnt have the cooler in place and was using the stock application, I still didnt have any issues with keeping the trans cool, but like I said its not a daily driver.
Let me know if you need any more help. I live in Chandler.

Thanks for all the info, I actually live out in buckeye so I'm a little far from you lol. I found a bar an plate style cooler kit at oreilly that I'm gonna try to get on this weekend. I've decided to keep the radiator cooler in the circuit, and probably gonna mount it on the drivers side so I don't have to run much hose.

do you watch extreme 4x4 on spike on saturday and sunday mornings? Well I was watching a particular episode that had to do with external coolers and Ian (the host) said to make sure you install the cooler on its side. Meaning have it up and down flat, like up against the radiator, and make sure the pick up tube line from the trans enters from the top and exits out the bottom.
If you look at the first pic, it shows where I connected the line to the top metal tube (which is the pic up tube on my xj). This went thru the ext cooler and back out to the line that leads into the radiator. The good thing about doing it this way is that you only have to worry about the pick up tube side and not the side going back to the transmission.
As for which side to install the cooler, I put mine on the passengers side. I dont see how having it on one side or the other will cause you to buy more line. You still have to buy line, just make sure you buy enough!

computer fans are dc and the computer actually had a power inverter/power supply built into them

For auto trans, this is what i did.

B&M 70268 SuperCooler Automatic Transmission Cooler: $56 Plus four 3/8" bolts, nuts, washers.

i mounted mine so it goes: transmission, cooler, radiator, back to the trans. someone said earlier that it needs to warm up and thats the same thing i found when i installed mine. i bought the biggest b&m my local race shop had at the time and it works great. keeps my trans around 170 or less even on the hottest days.

Anyone know what you have to do to change those lines from the cooler all the way back to the trans. Got the part just on the fence about doing it. 96 Grand Cherokee 4.0. Looks kind of involved. Any info would be awesome.