Saab 9-3 the standard offering, and a "HOT" (B204R, 200 hp) variant in the SE models for the 1999 model year. The 2000 model year saw a revision from SAAB's Trionic T5.5 to Trionic 7 engine management system. The T7 based engines were the B205L with and the B205R HOT engine with . The first generation 9-3 was also the first Saab available with a diesel engine, a unit also found in the Opel Vectra, Astra G, Signum, Zafira A. Unlike the Saab 900 (NG), the 9-3 is fitted with a CAN bus like the Saab 9-5. A Saab innovation is the
5-4-3 rule 5-4-3 rule The 5-4-3 rule also referred to as the IEEE way (contrary to the Ethernet way) is a design guideline for Ethernet computer networks covering the number of repeaters and segments on shared-access Ethernet backbones in a tree topology. It means that in a collision domain there should be at most 5 segments tied together with 4 repeaters, with up to 3 mixing segments (10BASE5, 10BASE2, or 10BASE-FP). Link segments can be 10BASE-T, 10BASE-FL or 10BASE-FB – for prompt collision detection, a full-duplex medium (not transmission) is required. This rule is also designated the 5-4-3-2-1 rule with there being