I had the slight "overrun" going into OD also, all I did was raise the shift 3-4 pressure 3psi and it cleared it up nicely. With 150,000 miles on it, it still shifts good.
I am thinking about getting one from a GT for the better gearing and rebuild it and have it for when the time inevitabley comes. Are the better gears worth it for a GTP, or does traction become a big problem?