any opnions on the best/ most sconomical/ best performance, etc.,etc.......

 

I know the Outlaw Power CAI is a quality unit on my 5.4L.

 

Aside from full-throttle operation at the dragstrip, there is very little to be gained with an aftermarket intake system on a gasoline engine. Under normal operation, like 25% throttle or so, your throttle restricts the airflow FAR more than the intake system..... to the point that any reduction in intake restriction would be trivial or less.

A diesel is a different story.

 

Some do filter air better than others I am sure, I guess a K&N filkter in the stock box will do.

 

There has been a debate as long as I can remember, but a replacement K&N filter will not "filter" any better than a OEM Motorcraft filter. The only benefit of using a K&N (and such) is that it is re-usable.

Be careful when cleaning...as the oil based filters tend to dirty the MAF sensor causing poor performance.

IMO...the dry type filters are better. Here is what I recommend...

advanced FLOW engineering
http://www.afefilters.com/
OE Replacement Filter with Pro-Dry S
Ford Trucks (99-04) (gas)
Part Number: 11-10004
MSRP: $45.49
UPC: 80295911006
Shipping Weight: 2 lbs

Hope this helps...

biz