Like I said earlier, I specifically asked why mine was removed when mine was redone. I was directly told, 'they aren't worth the effort, especially around here (the NW)'. Jeff (My builder) would have put it back on, but said that he removes every single one that comes through his shop. He said, I'll support you if it breaks. For what ever its worth, I went with it. Cooling has never been an issue for me and I just run the V10 cooler.
I always ran the stocker and another small one. I only had a few times it got really hot. Lasted 250k miles. I just got the bigger 6l cooler last week for my new trans since im not interested in the anal-retentive approach it took to get my stocker to 250k miles
Sonnax makes a kit that is said to deal with the issues of premature opening.