I found this how to guide, it includes detailed instructions and all the parts you'll need. It's for a Corolla, but the steering wheel is the same.
http://www.toyotanation.com/forum/326-c ... 011-a.html
It's REALLY important to make sure you get an OEM clockspring. If you aren't spending close to $200 it's almost certainly a knock off, and failure prone as Amazon reviews indicate.
Plus, as a bonus, you get the phone controls on the right side if you use part 8425002200, if you're connecting to an aftermarket radio which can use them. For aftermarket you'll still need a PAC SWI-RC interface v1.6.8 or higher:
https://www.youtube.com/watch?v=FxSzae_k4lE - or a Metra ASWC-1. You can also use the PAC SWI-CP5 which allows two functions to be assigned to each steering wheel button, short and long press.
In one of the pics, you can see the back side of the airbag where the base model "wings" would attach, and there's nothing there, so I would say it's safe to carefully trim them off to accommodate the new steering wheel controls, as long as you use a sharp knife and no power tools.