Rear end advice for racing with a 4 speed

Adding a Dana will not hurt handling or street manners.

These cars are all nose heavy in stock trim or anything close to it, and better balance improves handling far more than a small increase in overall weight will hurt it. If anything the Dana will improve F/R weight bias and may even lower the CG a smidge.

There’s a small increase in driveline losses, but that would hardly be noticeable, if noticeable at all, on the street.
I was just about to post the same . I am thinking o going to a Dana as it will improve the F/R balance and no more worries about broken diff if I hook up . Already broke 3 8 3/4