HID headlamps (optional) and a revised trunklid with revised taillights. Both available engines received a boost in power and torque, as well as slightly improved fuel efficiency. The 3.0 L DOHC V6 with which the LS was introduced now featured continuously variable intake cam timing, improved variable-length intake runners, and electronic "drive-by-wire" throttle control (which replaced the traditional mechanical cable-linked throttle control system used previously). The optional 3.9 L DOHC V8 with which the LS was also introduced received variable exhaust-valve timing. Due to its upgraded design, the 3.9 L V8 now produced over 87% of its peak torque output at only 2000 rpm and cars equipped with the V8 could now accelerate from zero to in around 6.5 seconds. Other notable additions to the LS included an electronic push-button parking brake (similar to that of the BMW E65 7 Series), replacing the traditional center console-mounted hand lever (or foot pedal), a touchscreen DVD satellite navigation map system, and an industry-first, 10-speaker THX-certified sound system. LSE versions were also available in the 2004 and 2005 model years, with unique fascia, unique 17-inch wheels, all-red tail lights, a color-keyed grille, unique floormats, and additional wood paneling in the interior. Earlier LS models had a mechanical engine cooling fan that was operated with a hydraulic pump because the electrical charging system did not have sufficient capacity to effectively power an electric fan. A later revised alternator enabled the implementation of an electric fan for the 2003-2006 models. The 2003-2006 GPS navigation system uses a DVD player mounted in the trunk (under the package tray) to contain the map data. For 2006, the LS received exterior revision similar to LSE fascia trim from previous model years. The V6-powered model was dropped from the lineup. The base MSRP increased from $32,370 in 2004 to $39,285. Safety The Lincoln LS has received very high marks in occupant protection. The Insurance Institute for Highway Safety has rated the LS as a "Best Pick" with a perfect score in their frontal offset crash test. The National Highway Traffic Safety Administration gave the LS almost perfect scores in its side-impact and rollover tests. In fact, CNBC rated the LS as “one of the five safest cars of all time.” Model naming controversy Lincoln originally intended to designate LS models as "LS6" and "LS8", depending on the engine size option. Toyota threatened a trademark infringement lawsuit, due to the