DIY cold air intake pipes?

I'm new at this, so forgive me if this is a dumb question.

I've been reading lots about using cold air intakes to improve power and mpgs. I priced out a few of them and am surprised to see how much they cost... isn't it just a tube and some hose clamps with a filter on the end? Unless I'm missing something big (more than likely), couldn't you just buy the filter and then run a pipe or tube to a good spot for the intake?

 

You will not get better mpg.

 

Well, in theory you could do this.But i would only buy a toyota TRD model. I figure they made the engine...Why reinvent the wheel ya know?

 

And it will only soound cooler. Just replace your factory airfilter with a AFE from auto anything. Those seem to be the best by popular vote

 

Stick with stock.. $16 and they're good for 30-50k.
Toyota knows what they're doing.
The stock intake can flow more than any normally aspirated 4.0 can draw.
"Cleanable" filters pass far more dirt into the engine, which will score the cylinder walls and lead to increased oil consumption as the engine ages.

 

Well if you want better airflow then yeah drop an AFE Pro Dry-S they do improve on airflow and performance (to a slight degree) but if you want unmatched filtration then yes Toyota paper is very good at that. Gotta trade off something for something else usually