Another way to increase the air flow is to increase the size of the filter. A paper filter with more surface area will also flow easier and still provide better micro particle filtration than somehting like a K&N. But it may be difficult to fit in the engine compartment depending on your setup.

However, with today's computer controlled engines that constantly try to keep the F/A mixture at the proper ratio, more air flow will do little (or nothing) without changing the fuel map code. (Re-Flash as someone mentioned earlier).

There is also the possibility that the exhaust is restrictive enough such that opening up the intake would make little (if any) difference in air flow.

The ICE in the TCH is also has valve timing such that the intake valve is held open longer than normal in the compression cycle (simulating an atkinson cycle). So some of the intake charge is already pushed out BEFORE combustion (resulting in less power, but more efficiency). In this case would the less restrictive filter allow MORE air to be pushed out, thus reducing, or even eliminating the intended effect?

So NO, more air flow is not necessisarily better for the engine. I would agree with the consensus to stay with the stock filter, with some rare racing and/or replacement cost exceptions.

 

Well said ability for rare racing and replacement cost are my main reasons but not only that

How clean air coming to the engine from recirculation of exhaust gases, crankcase ventilation, PVC system? Are those systems have paper filters?

 

K&N says your comment the filter will destroy MAS Sensors is a myth. I suspect your comment applies to the TRD filter as well. I have used a TRD filter in my 2005 Scion xb for 55k miles - still waiting form my MAS sensor to go bad. To quote an infamous US Congressman "You lie!"

http://www.knfilters.com/MAF/massair.htm