Other than elevated silicone reading in my UOA and a slightly nicer low-end (low rpm) grunt (sound wise), I trashed my K&N after a year of usage in my Mazda 323 back then.
I wouldn't bother with air intake or filter mod anymore, citing (a) almost no gain in performance (OBD-II ECU are very controlling, and can compensate for your K&N replacement), and (b) the ever-concerning elevated silicone readings in UOA.
05+ Tacos already come with CAI from the factory. Other than opening up the airflow a bit, there is no benefit to an aftermarket CAI. K&N for the Taco actually pulls air from the engine compartment as well as some air from the outside. The heat shield that K&N supplies with their intakes does about as much good as a fig leaf on an elephant.
Plus there is always more silicone going into the engine with K&N. If you just want a permanent/cleanable filter, look into AFE drop-in replacement for the factory filter. I've heard nothing but good things about them over at toyotanation.
A little more power at high rpms, a little less at low rpms, and a little more dirt in the engine. Unless you really need that extra couple of horsepower at high revs, I'd do something else with the money.
The intake will probably get a bit of power at full throttle .
But upper intakes like this are very expensive in the HP/dollar game.
For your stock system, make sure the actual end inlet is not a tiny restricted hole. You can often open this up and make a home made improvement, like a piece of PCV pipe grafted on - whatever.
An underdrive crank pulley is a very good gain per $, BTW.
Your light may dim a bit at idle, but a very nice improvement for $100 or so.