My oil cooler is a bit bigger than the DDMWorks one and it is front mounted in front of the radiator. I would imagine I get a bit more of a cooling effect than having it side mounted.
The Evans flush isn't complicated per se, but it is a bit of a pain in the ass. I pulled the hoses at a couple locations and used my shop vac to blow air through the lines. It makes a bit of a mess. Then I ran some flush through it, getting up to operating temp, let it cool and drain again. Then I blew air through the lines a second time, tightened everything back up and filled it with the Evans.
Guess we can save that mess for another wrench day.