It's too early to tell. If he exceeds the expected lifespan of the truck by topping say 400K, then you can start giving the mods some credit.

 

Please explain to me how a MAS, TB spacer, and CAI can help the longevity of an engine.

The original question was whether or not a CAI could/would provide increase milage or throttle response. I still do not understand where we are going with this.

 

No, I don't want to.

 

I will have to remember to use tastier bait next time

 

What all did you buy and need to do this? I want to do the same but not sure exactly how. I have a 04 expy with the 4.6

 

Mine was 03 with 4.6 also. I got everything at Home Depot, Lowes would probably work too. I got 3" ABS plastic pipe, at my Poe it is in the same aisle as pvc pipe.
Across the aisle, in my Poe, are rubber couplers used to piece pipe together. The couplers have hose clamps at each end and will fit over the end of the ABS and the stock intake tube/inlet. Test the coupler against the ABS I can't remember the size I picked up. I'm assuming you saw the steps of the thread on removing the choke down tube from the stock intake.
You will need to grind the ABS some to get it to fit into the hole the stock intake tube came out of.
Let's face it 4.6 isn't a hipo engine and even with an updated intake the power will come from getting the gases out of the engine faster. That being said it did increase my throttle response and had a killer sound to it.
Hope this helps.