I don't know about the 04. 5, but I can tell you from experience on my 04, the EGT's stay cool enough, without a boost elbow. As an experiment when I first got the downloader, (even though the programming wasn't right at the time), when I put it on the dyno, we plugged the wastegate to see what would happen. There was absolutely no change in EGT's or power, even though the boost was up a few pounds. From what I understand, the stock turbo's on these trucks start getting out of their efficiency range beyond about 30-35 lbs. I'm sure BullyDog took this into account when doing the programming, and that's why they don't require a boost elbow.
Jim