A few Coworkers of mine have VERY similar trany pans on some of there trucks, with the cooling fins and such. They all leak at the drain, no matter what. And i work in a transmission shop....you wont catch me running something with a drain plug on it as such.

I have had a drain plug on my aftermarket trani pan on my Firebird for over 20 years.
It doesn't leak. Maybe because it has a teflon gasket washer.

Another trick is a light smear of RTV after a good degreasing.

I think that the 20 - 30 F cooling would nicely supplement a trani cooler.

Cooling would be really nice...but for those that want extra magnets on their pans they'd have to give that up.

That is mighty expensive though. I don't know the temp of my '03 trans yet, or what others run, but my 94 ran at 160* at it'* hottest with the stock cooler. Unless your trans is running close to 200*, 20–30 degrees cooler would be too much I'd think.

My trani matches my coolant temp at 160 F until I run at highway speeds in hot weather or really lay into the throttle, then it will rise to 190 - 210......... and I have a large aftermarket cooler added.