Drtom has a interesting point! Im all about keeping around 2k rpm kind of guy. Will a CAI be useful to me? Im all about the MPG's! Great post.
The exhaust I know would be beneficial across all RPM's and the PCMtune is the ultimate upgrade for mileage gains, (on the wish list).

 

I hear ya on not spending much time at 4000rpms, but I noticed a nice gain from 2500-4000 as well which I need for chugging this 3.5 up all the inclines I drive on. It doesn't downshift and bog down nearly as much. I'm very happy with it still.

Tomsbeast, here are some pics of the k&n and spectre. Already assembled but has some divots in one part of the tube ($8 pc) from the coil pack.

 

Hate to beat a dead horse, but lower RPM + increased power = lower fuel consumption vs. Higher RPM + increased power right?

Just trying to figure out if CAI is worth the money if you dont plan on racing this thing? I climb 20% grades every day with my 3.5 and achieve this at around 2300- 2500 rpm. At 40mph it will upshift and drop to 1800rpm till speed decreases to 35mpm (as long as you maintain steady pressure on the skinny).

I had read somewhere that if your not going to be putting your vehicle up int he 3k+rpm then a CAI is useless.

 

Nope. every engine has a sweet spot in the rpm range that it gets the best fuel mileage. I know guys with 500hp sbc getting over 20mpg. This also is effected by gear ratios, trans shift points, tires,etc. You just have to play with things or find someone who has already done the work for you, and trust their advice.

 

The Injen has 3 type intake filters the two most popular would be the Cold Air intake and the Short Air Ram.

The short Air will give you more HP and Torque in the low end and take offs. Its just what it says Short Ram Air, so it intakes warmer engine air from what I have read up on them.

The cold Air Intake will give you more mid to top range HP because it taking in cooler air and a longer tube..
I may be wrong, but this is what I have read ....

 

i think you find long pipes do low end and short pipes affact high.
that would fit with basic resonance/tuning systems