At this point I'm getting pretty consistant 32+ MPG tanks (combined city/highway), and I can usually get 34 MPG trips on my commute. Tires at 40psi (rated for 35), radiator block, and WAI. After several attempts on the WAI, I'm now using 2" clear tubing from Lowes - it's stuffed in the air intake and directed to pull air from where the o2 sensor is mounted because there is a hole in the heat shield there). I monitor my coolant and intake air temps. coolant floats between 190~210, and once up to temp the air intake can exceed 80 degrees. Anyway, not too bad for a car that gets new epa 28 highway!