hi all just fitted my diff but do you need to have some sort of rubber bushes to stop any vibrating. cheers

you don't have to but you can rubber bushes if you like. Leaving them out just means all the gear whine (quite loud) gets transmitted to the chassis. Plastic bushes will also be very noisy.

The MK chasis are designed for the diff to bolt solidly direct to the chasis plates.

As Whippy says, you will notice more gear whine than on a Sierra, but then the diff will be 4" from your arse behind a 1mm thick ally panel and anyway, once you engine is running and your moving you won't notice it at all