In most vehicles 2x or 3x Hiclones will work very well for you and 4x units if you have a snorkel, we suggest you put them all in at the same time and see how they go over the next 30-50 days then if you want to, take the one out at the filter end, if you think you don't need it give me a call and send it back, basically 1's good 2's better 3's best and 4's the ultimate.
Use our online fuel economy calculator
to see what your getting from your fuel, it may surprise you.