The Veloce 4.1 open diff will likely serve you well.
Modern tires are so much better that the best available in the late 1960s. Then a Giulia with only a modest tune and aggressive road driving would generate some spin on the inside rear wheel. On a track without a lsd wheel spin was hopeless.
However, the Continental Contac Pros I have on the Spider have much better grip in the dry and wet.
These are 175/65/15, and were made for the first version of the "new" Mini Coopers.
I can get some more HP out of the 2 L and the lsd will, at times, be worthwhile.