Although this is a good thing to do, it's a little overkill. You can get a seal that will fit into the o-ring groove. Look to your local o-ring/oil seal dealer and ask for a "9815" seal. The dimensions are 1id x 1.125 od x .125 width (just like the oring). The trick with this, which is far less invasive than the alternative, is to heat the housing around the kickshaft bushing and pop the bushing out. I laid a few drops of Red Loctite in the seal/oring shoulder and dropped in the seal. Then chill the bushing to replace as to not disturb the seal. Vwa-la.
Due to the fluid level and the fact that I have never seen dripping from the shifter shaft, I left well enough alone. The $.75 oring swaps out with no trouble at all. However there is a seal that will fit that also(6152).
This is good alternative upgrade that anyone can do and will cost around $6.00.