Can any tell me if it is an easy swap to put Toyotas own Diff lock center into the standard diff. I can get a diff center complete with wiring harness switch etc, and just wondering if the swap is relatively straight forward.
Cheers Zack..

the front diff housing is slightly different where the centre bolts in. A standard housing would need a little bit ground away where the diff lock actuator needs extra clearance to fit into the housing. I think a couple of bolt spacings are slightly different too.
I used a standard gasket when I had my front diff centre out, I had to trim it a little and put a extra hole or 2 in it.

I havent looked at the rear, but would assume it would be a similar scenario.

I think the front inner axles are different lengths too, though someone would need to confirm that, Im not 100% certain. A visit to your local helpful toyota to check part numbers might help confirm this.

If you can get the inner axles as well as centres and your not shy with a grinder, Id say go for it.
I can not fault my factory diff locks. They have been awesome.

The only thing I dont like about them is the position of the switch. I will be setting up new switches so that they are more accessable and so that the front and rear lockers can be switched independently.

This subject has been covered before, have a read here

have a look at these for an idea on whats involved. all american sites though most info will be relevant

http://www.sleeoffroad.com/technical/tz_retrofit_lockers.htm

http://www.bajaoverland.com/elocker.php

http://forum.ih8mud.com/80-series-tech/26446-retro-fit-locking-diff-non-locked-housing.html