Totally agree with everyone else here, unless the suspension has been modified and you're running tires rated for higher speeds than the stock tires you should leave this alone. Just because the speedo goes to 140 doesn't mean you should drive 140. Like some of the other posters here; i've had mine up to about 110 and the truck felt VERY unstable, was only a short burst down the interstate with nobody else around. Mine is on stock tires, stock height 4wd big tow package.
Removing the speed limiter to get to town a little faster sounds like a nice way to throw 20k out the window and kill someone.
Lets pretend for a second that you were in a hurry to get somewhere. Traffic on the interstate is light and most everyone is running at 80mph...
You've got to get to an exit 10 miles down the road.. It will take you seven and 1/2 minutes to get to your exit if the flow of traffic remains constant.
If you decide to stomp on it and run at say 113 mph which is 33 miles per hour faster than everyone else now requiring you to have to weave in and out of traffic... Your 10 mile drive at 113 mph will take you 5.3 minutes to complete...
If you removed your speed limiter and drove at 140 mph which exceeds the safe rating on stock tires and is way to fast for a stock suspension & height you would make your 10 mile drive in 4.2 minutes...
Now lets look at the results..
Driving 80 mph, takes us 7.5 minutes to go 10 miles.
Driving 140 mph, takes us 4.2 minutes to go 10 miles.
We've manage to save 3.3 minutes if we were able to maintain a constant 140 mph and keep control of the vehicle while weaving in and out of traffic going 60 mph faster than they are..
When we get to the top of the exit ramp the light will probably have just turned red anyways.
If you increase the time you obviously get more savings, but could you honestly think of a reason you would need to hold the truck at 140 mph for a long distance say 100 miles?
Same Numbers 100 mile distance:
Driving 80 mph takes us 75 minutes to travel 100 miles.
Driving 113 mph takes us 53 minutes to travel 100 miles.
Driving 140 mph takes us 42 minutes to travel 100 miles.
Overall savings in time: is 33 minutes if we were able to maintain 140 mph for 100 miles.