- the backing plates for the pads they've fitted are very slighter smaller, allowing them to move back/forwards inside the calliper so giving the clunking.Easy fix
- Toyota do (ISTR) a Brake Shim kit from Toyota which includes the normal back of pad shims, as well as the shims to go under the 'pad support plates' at either end to stop the pad clunking about, which sounds like the problem you've got.