I suppose it depends on how comfortable you like your daily driver to be. Larger tires equal worsened mileage, loss of power, more drivetrain wear and tear, higher replacement costs, an even more filthy rig, longer braking, and worse steering performance on rutted pavement (the great majority of pavement where I live).
My Jeep had 35s for a year. I changed to 33s and it made a huge difference for the better. Of course the Jeep doesn't have the long wheel base or horsepower of your rig.
In short, yes, you will notice a difference between 37s and 40s. Everything that is generally considered to be undesirable in a truck (for comfort and drivability) will be amplified. You might be able to mitigate the negatives with 5 - 10 grand worth of suspension work though. Not sure of the cost to upgrade...but it will be considerable.
Would you regret it? Maybe not. I still have bigger tires on two of my rigs. They are fun and cool! It's nice to know that you can probably roll over most terrain without worry.
When I have a long road trip or the roads are really crappy I leave both big wheels at home at drive a car with factory-size tires on it.
Different strokes though.
