I've done this retrofit using the one-piece 1999-2005 plastic housings which are in the same style as the 2006-07. It is pretty straightforward, you can see them in my post history. The DEPO housings I used may be slightly different than the OEM Toyota housings. The sketchiest part is widening the bulb opening to fit the Mini D2S collar, as that is the point of no return.
My advice would be to find a generic headlight and practice the opening/cleaning/widening procedure to decrease the risk of damaging the OEM housings.