The Subaru Impreza WRX STI is the highest standard-edition trim in the Subaru Impreza line. In 2001, the Impreza line received a complete update. The chassis was stiffened so that it had 120% torsional stiffness increase. The WRX STI gained 17" x 7.5" alloy wheels over the previous 16" x 7" wheels. The 5 speed transmission (reputed to be one of the car's weakpoints) was changed to an STI engineered 6 speed manual transmission. The engine was retained from the Version 6 STI and still retains the semi-closed deck block and is still labeled as the EJ207. However, the turbochargers are IHI models. The interior was updated with a STI logo on the gauge.
The STI's gauge also has a red shift light. The STI's and optioned Type RA STI have received Brembo 4 pot front and 2 pot rear brakes while the bare-bones Type RA STI still carried the Subaru 4 pot front and 2 pot rear brakes. Externally, the STis had larger hoodscoops and had foglight covers with STI embossed on them. The DCCD was updated so it can work with anti-lock brakes. During braking, when the ABS is on, the DCCD will set itself to open-mode (no locking).
Source: Subaru Press Release