That is an electronic regulator and is an upgrade to the original electro/mechanical unit. As long as your existing alternator has enough capacity there would be no need to change it.
PANTERA INTERNATIONAL
A DE TOMASO CAR CLUB
Presents the De Tomaso Forums
The On-Line Meeting Place for De Tomaso Owners and Enthusiasts From Around the World
Clicking on the banner will take you to the sponsor's website.