Air Filter
K&N 33-2363 (online) or K&N 332363 at Advance Auto Parts. $52 + tax. I got INSTANT performance boost. INSTANTLY noticeable performance boost!
See my other postings for my chase to get above 14mpg.
~30 days ago, I bought a fully loaded 2007 SLT 4x4 (plus 20" R/T wheels/tires too). I was only getting 14.4mpg in city until my recent "maintenance kit."
- NTroGN