I have an 87 930 with 50K miles on it. I had the same problem as Fairman until last weekend when I drained the transmission and replaced the fluid with Swepco 201. I had problems at stoplights getting it to go into 1st...and sometimes into reverse. Since I've switched to the Swepco, the shifting has improved dramatically, although I think that the 930 four-speed transmissions will always be somewhat difficult to shift into 1st and require a soft touch. They don't like to be hurried, and sometimes I shift into 2nd then into 1st if it balks on me. Bottom line is that it's been much smoother and easier to shift since the switch to Swepco.
1987 factory Slantnosed 930 Cabriolet/Guard's red
2002 Midnight Blue 996TT X50
1999 Iris Blue 996 (Dash fire burned and totalled 9/07)