After doing a little research and asking a few people for recommendations,
I've chosen Fred Brown Performance Transmissions in Bay Shore, NY.
http://www.fbperformance.com
Since my Dealer had to go to Bay Shore to get my Marauder,
I figured I'd have to bring her back home to get any major work done she needed.
They are going to do a full PRO STREET rebuild of my core, add a 300M Input Shaft,
and rebuild my Torque Converter with new parts/stronger parts where needed.
I asked about my differential, and they suggested getting rid of the pos factory one and getting something stronger.
I've always wanted a Torsen and they agreed it would be a very good choice.
They are getting prices on the Torsen now, and will reuse my gears
as long as they are in good shape.
Since I've been changing the oil every 30k miles, they should be in good condition.
My Marauder has seen mostly highway miles and only lightly loaded.
If everything works out well, I will be bringing her to Fred on Monday
and back home before the end of the week.