I love it how a forum thread will just sit there and wait for you to earn some money, collect some parts, crank on some wrenches, and report back later. So here is my March 1 update.
I bought a 12-bolt housing with 33-spline Moser axles, c-clip eliminators, 4.56 gears and a 4-series spool from John (member here). From the advice in this thread I decided to install the 12-bolt as purchased to evaluate the characteristics of a spool driven on the street. I knew the 4.56 gears wouldn't stay long - they are crazy in a street car. My experience with the spool was more positive than negative. It is pretty un-noticeable while cruising. About the only time I feel it is maneuvering in my driveway or parking. It does increase the turning radius, and it does make it more difficult to roll the car with the steering turned. But for the cost and reliability, a spool can't be matched.
So this past weekend a friend helped me swap the 4.56 gears and 4-series spool in favor of 3.08 gears and 3-series spool. I also added a cast aluminum cover/girdle. Now with my 28" tall street tires it cruises 2,300 rpm at 55 mph. the car is much more enjoyable to drive than either the 3.73 or 4.56 gears.
I also recently installed a boost controller that is time based so I can progressively bring on power as my small tires can handle it.
Huntsville Dragway will open up next weekend (depending on weather) so my next update with actual performance numbers should be coming fairly soon.
I want to thank the many people who gave opinions, advice, and personal experiences in this thread. As you can tell, you were instrumental in helping me through the rear differential decision process. Also thanks to John for selling me his "cast off" 12-bolt assembly.