This manual covers the 300 / 300C STR-8 model produced in 2006. Built on the LX platform, this vehicle is known for its powerful HEMI V8 engine, delivering approximately 425 horsepower and 420 lb-ft of torque, coupled with a 5-speed automatic transmission featuring AutoStick capability. The STR-8 designation highlights its performance-oriented SRT tuning. This model offers a blend of luxury and performance, featuring standard safety systems such as ABS, traction control, electronic stability control, and multiple airbags. Its design, shared with Mercedes-Benz components, reflects a commitment to engineering quality and a robust driving experience. This factory service manual provides comprehensive factory-level diagnostic and repair information in English, formatted as a fully printable document. It details engine service, transmission repair, brake systems, electrical systems including wiring diagrams, suspension, steering, cooling, fuel, emissions, HVAC, engine controls, chassis, body, restraint systems, and interior components. The manual includes step-by-step repair instructions, advanced troubleshooting guides, diagnostic procedures, rebuild instructions for major components, and periodic lubrication details. With detailed illustrations, photos, and enlarged insets, this resource empowers vehicle owners, DIY mechanics, and professional technicians to maintain and repair their 2006 300 / 300C STR-8 effectively.