The Extra 300L is similar to the Extra 300, but with the wing in a lower position (hence the "L"). The lowered wing allows for better pilot visibility. It also moves the wing spar structure to the floor of the fuselage. In the Extra 300, the rear spars attached to the fuselage right where the back seat instrument panel area resides (this is the pilot's instrument panel, since the pilot takes the rear seat). The heavy stucture here complicated the installation of IFR avionics due to the tight fit. With this intrusion moved, the 300L can easly be fitted with a full IFR instrument panel. In such an installation, a gryo attitude and direction indicator would be fitted in the center of the panel. Non IFR competition 300L's will typically have a plexiglass panel placed here, which is used to hold the Aresti notation diagrams that map out aerobatic routines.
The 300L has wings, fuselage and tail structures similar to the 300, but many of the fuselage panels have been replaced with composites.
Flight characteristics are also similar to the mid-wing 300, though both inside and outside snap roll behaviour is improved, and the roll rate is slightly higher.