A little update after putting a few miles on her; took a nice 400 mile trip to go camping this Father's day weekend with the 5er in tow.
After the turbo went in, I did an initial hour or so of driving the 5er around to check the EGT's, and I could run it right up to 1100 degrees pretty easily. So I turned the pump down one flat (now it's only turned up 1 flat from where it was when it was NA), loaded the family and trailer up and headed out.
To start, my previous trailer hauling was done with 33" tires; It's now sitting on 35's. My trailer is 31' long, and weighs in at about 10k pounds, so I'm just under 18k gross by the time I load up the family, dog, bicycles, firewood, etc.
Before the turbo, I couldn't hold 3rd gear on the steeper hills, which meant 3000rpm in 2nd gear which netted about 30 mph.....painful
After the turbo, it can now hold 3rd gear, which means 3000rpm in 3rd (remember the bigger tires, too) = 50 mph.
I saw about 9 psi of boost and the EGT's only crept past 1000 on one occasion. Coolant temp never went above 200. And it just sounds awesome hearing the turbo whine. It got just above 10mpg on the trip - although I was definitely not going for mileage. Did I mention I like hearing the turbo whine?
For the most part, I was going just slightly slower everywhere than I would have unloaded. Made the whole trip way easier and less stressful than before the turbo.
My previous truck was a 97 PSD that was bone stock, same size tires, but with an auto and 3.55 gears, and it towed the same 5er up the same hills at the same speeds.
So my conclusion; on a daily driver, a turbo isn't going to really get used a whole lot, but if you're towing heavy fairly often, I'd almost call it a necessity.