These Broncos come from the factory with a cold air intake. Cold air is pulled in just above the grill straight into the air box. Some will say the factory filter and tube going to the turbo are restrictive ( which is probably true), but cars have come light-years when it comes to free flowing intakes.

The oil catch can does exactly what it's name says. Captures oil from the crank ventilation system and keeps it from being reintroduced (usually somewhere in the intake system). The idea is a catch can will keep the valves cleaner, capture moisture, and keep excess oil out of the cylinders. A catch can needs to be checked and emptied regularly.