[ATaylorRacing]

All of this depends on the car itself. I mentioned earlier from a post I made on 9-12 that improved air flow made every one of my cars go quicker and get better FE....I was shocked that this was NOT the case on my 96 Geo Metro 3 cyl! Going from the stock air filter to a home made CAI and fine wire mesh for a filter made the car consistantly loose nearly 2 mpg on the hiway!!! Using the stock air filter but keeping the CAI made the FE worse than the stock set up by about 1 mpg too!