I changed the filter earlier this morning, and I even stopped along the way for a few pics. I hope this will show that you don't have to be a mechanical genius to do it:
1) Open the hood. Look between the engine block and the battery. The airbox is roughly the size of two small loaves of bread, stacked. It will have a big hose running out the front.
2) Use a screwdriver or 10-mm wrench to loosen the screw clamp; disconnect the big hose from the airbox.
3) See the small hose branching from the big hose, leading to the engine block? Loosen the spring clamp and disconnect the small hose.
4) Pull and unfasten the two clips that hold the airbox together at the middle.
5) Separate the top and bottom halves of the airbox, and you will be able to pluck the air filter right out:
6) Install the new filter and replace everything back where you found it.
kneisl1: A casual glance suggests that the aftermarket filter may actually be better than the Toyota. As you can see below, the Purolator (left) has deeper pleats and more of them, creating more surface area for filtration:
Only a lab test would be able to compare the actual efficiencies, of course.