I agree that freeing up the airflow will help any motor.
I haven't had the funds to do it to my current truck yet
but my previous truck ('02 Ranger 4x2) gained 3-5 MPG and
nearly 20HP by just increasing airflow with a K&N drop
in filter in my modified air box and Gibson cat back
exhaust. I was getting 25 MPG while pulling my 1500lb
utility trailer loaded with camping gear over Mt. Hood!
Of course that was the 2.3L motor too, but still pretty
dang good IMO.

Regards,
Indy