Well, there are a few things a mechanic will consider before he'll make the change. One is that the limiter isn't a plate, it's controlled by the computer, and the computer would have to be reprogrammed depending on the make and model of the car.
Another is the speed limiter is set based on one very important safety factor, the maximum speed rating of your tires. My guess is that the maximum speed rating on your tires is somewhere between 91 and 106 mph. Until you put speed rated tires on you car, it isn't safe to 'make it go faster'.
One thing a good mechanic will look at is your brakes. If you can't stop on a dime from 100 mph, why would a GOOD mechanic allow you to go faster without a brake upgrade (usually performance pads, and some combination of slotted/cross drilled rotors).
Now assuming you've got the right tires, and can stop safely from high speed, then I'm sure a GOOD!!! mechanic can either install a new chip for you, or make the changes you'd like to have made. Depending on your car and where the chip or add-on chip is located, you're looking at about a $200 to $400 job.
Hope this helps, but until you can do this right, stick to the speed limit. You'll live longer.