As far as I know, there is not a specific conversion kit. (it is hard for the factory to do a kit, because it depends a lot on what you are running in terms of model and options)
The way I did it to convert a T3 '11 to a T3 '12 spec - download the Excel Parts Cross Reference Table off the X-Ray website, and then use Excel filters to show the new "standard" parts on the '12 relative to the '11, and order them individually.
In essence, the parts were:
Bulkheads (if you don't already have the clamp-on bulkheads, I did)
Chassis plate
Top deck
Shock mounts
Servo saver
Gear diff (if you don't already have one - I did)
Steering arm
Hard steering block (I did not change this)
It looks like the list is longer for the T3'10 conversion
HTH
