It was removed due to fitting the stock 5 speed gearbox back into the car.
You'll need the Shifter, Front Prop Shaft, Rear prop shaft and clutch from the R34 GTR to fit onto R32 or R33
As to modifications the, speedo does plug straight in however, the reading will be incorrect, you'll need to recalibrate the speedo.
hope this helps, please do let me know if you have any more questions,