Gotta say it was damn frustrating Sunday due to the fact that I was so overgeared with the 33 5-speed box that I had in me car. I really missed me 6-speeder I can tell ya. I couldn't even get out of 4th on the Top Speed Run .
CHEEKY, THATS MY NATURE, KIND CARING SENSITIVE PERSON WITH THE UPMOST RESPECT FOR MY CAR, NOT ONCE HAVE I GONE - SMASH INTO FIRST, SMASH INTO SECOND, SMASH INTO THIRD, SMASH INTO FOURTH, SMASH INTO FIFTH, SMASH INTO SIXTH - OK MAYBE JUST A FEW TIMES, HEHE.
It won't fit into earlier models without a considerable amount of work. You would need at least different (read R34) diff ratio's and a different main drive shaft. You also might find that the gearstick is not exactly in the same location; the body shape might not fit either.
If you want a 6 speed box, you can get conversion kits (e.g. Quaife/Greddy, straight cut) or a Hollinger sequential box.