Wow you couldnt be more wrong.
The jdm d15b that came in the 92-95 was only a normal vtec motor.
The d15b that came in the 96+ was a 3 stage vtec which has 2 vtec solinoids on it unlike the normal vtec motor that has 1.
It is not only in the ecu like you state it is the motor itself that is different
The 3 stage vtec is a motor honda made to be both a gas saver and have a little performance aswell. (for a d-series atleast)
wow....rep for your honda knowledge.
....when I can.