[spacemanspif]

Best way I have found to limit speeding is by not being late before I leave the house. If you didn't feel rushed, you won't think you need to drive faster to make up lost time.

Any computer flash can set a governor, popular brands are HPTuners and SCT and COBB accessport. Some companies encrypt and lock their ECM, HPT and SCT have been tuning GM and Fords for years. If this is actually something you'd want to do to the car find a speed shop in the area and ask what cars they can and can't tune and limit your search to those they can tune. I picked up HPT on Craigslist for a good price which enables you to tune the computer from a laptop. Pretty sure SCT and COBB are mail-order type tuners.

The best situation here is a "valet" key. A lot of keys in modern cars have RF transponders for anti theft protection. If the computer can recognize different keys, 1 can be the slow key and another the regular key...I believe the hellcat or demon have this feature along with other hi performance cars.