Hi,
I have installed this radiator in my car. There is no need to update the DME.
Coolant temps will indeed be a little bit lower but when tracking the car in hot summer temps on a road course, it won't be sufficient to prevent heat induced limp modes on 6AT cars. I have first hand experience with this
This radiator is an ok upgrade which will overall help a bit with engine cooling. It also helps to bring temps back down faster on a cool-down lap. It's just not enough for hard tracking.
A dedicated tranny cooler is what 6AT cars need as that will prevent the transmission oil from heating up the coolant further through the heat exchanger in the stock radiator.
Here's a pic from two weeks ago. You can see I deleted the fog lights to get more air to the cooler.
