Never been out of the 1st gen durango section, but saw this.
I called Airaid and asked about the throttle body spacers and the guy said this to me:
The throttle body spacer does not increase horsepower
It does not increase your 0-60 time
Nor will you see any change in time for your 1/4 mile
He said what it will do is increase your torque under 3000 rpm
the throttle body spacer increase torque on the low end for daily driving and to increase fuel economy.
This being said it is just an aluminum machined piece which swirls the air before it enters the throttle body.
So i dont think you need to spend 100+ dollars on one when you can order the helix power tower or a generic brand off ebay for half the price