you can open it up and either remove the part of the button that bridges the contacts, put something non-conductive across the contacts, or sever the contacts themselves.
As for an extra key, not sure why it would be needed. You can always get an extra key cut that will open the doors, but won't start the car without the transponder chip.
Sonic's Mk3 Crew #11
Originally Posted by suss6052
Watch out for the D