It’s worth taking a look at the “Electric Classic Cars” channel on YouTube. They recently completed a Ferrari Testarossa and claim to have improved the weight distribution whilst maintaining the overall weight the same as pre-conversion.
Several of their videos reference managing the weight of a conversion to preserve handling characteristics.
What they do not reference very often is the range they are getting.
A friend of mine has a 1990 Testarossa, one of the few Ferrari's that has yet to come of age from an investment point of view. For what was I suppose a grand tourer, if you used it's potential to the full, you were stopping to refuel far too often. Extremely expensive to maintain, not that fast compared to some modern cars that would show it a clean pair of heels, so I can understand why a perfect candidate for EV conversion..........I assume the range was pretty restricted maybe 100 to 150 miles if they kept the weight the same.