Whats the best air intake type ?
The best air intake type is usually the one that comes on the car. All cars are made with a cold air intake and putting aftermarket intakes on any car, just uses your money and you might get a nicer sounding car but they will not give you any extra power or mpg saving. My opinion is CAIs are a waste of good money.
Depends on your car. Sometimes just a drop in high flow filter is all you need and other times your need the entire air intake housing.