LSD And diff gears in my opinion too, i got 3.46 gears LSD, good for a car not producing tonnes of tourque
My speedo is out like 2 - 3 kms though, but thats because I have 19s (bigger wheel size) and a 3.46s.
Anyways, it is worth re-building or getting a rebuilt diff, 3.46 on a freeway...