Fujitsubo Authorize RM Back Box & Diffuser (Unpainted) Mazda MX5 ND (Mk4)

The Fujitsubo Authorize RM Back Box is a lightweight, performance-focused exhaust system developed for the Mazda MX-5 ND equipped with the Kenstyle rear aero package. Combining a stainless steel muffler with a striking titanium tailpipe and a matching Kenstyle rear diffuser, the Authorize RM delivers enhanced performance, reduced weight and an aggressive motorsport-inspired appearance. Designed for sports and track-focused driving, the Authorize RM range prioritises mid to high RPM performance with improved engine response and a more pronounced exhaust note than Fujitsubo's street-oriented Legalis systems. Precision manufactured in Japan, the exhaust offers exceptional fitment and build quality while reducing overall weight by approximately 1.6kg compared to the factory rear silencer. This package includes an unpainted Kenstyle rear diffuser, providing the correct styling and clearance for the titanium exit, making it a complete upgrade for compatible ND models. Features Stainless steel muffler with titanium slash-cut tailpipe Approximately 1.6kg lighter than the factory rear silencer Includes unpainted Kenstyle rear diffuser Precision manufactured in Japan Performance 50-100km/h acceleration (3rd gear): 3.1 seconds (standard) → 3.0 seconds Maximum power: 117.8PS @ 7010rpm (standard) → 120.7PS @ 6880rpm Maximum torque: 145Nm @ 4350rpm (standard) → 146Nm @ 4550rpm Specifications Muffler material: Stainless steel Tailpipe material: Titanium Tailpipe diameter: Ø70mm Tailpipe style: Slash-cut Pipe diameter: Ø50.8mm-42.7mm-45.0mm Diffuser finish: Unpainted (will require prep and paint before installation) Weight: 10.3kg (standard) → 8.7kg Idle noise: 62dB (standard) → 65dB Noise near exhaust: 88dB (standard) → 90dB 3000rpm: 75dB (standard) → 83dB 5000rpm: 87dB (standard) → 86dB Response noise (4000-6000rpm): 97dB (standard) → 107dB Kit Contents Authorize RM rear back box Kenstyle rear diffuser (unpainted) Collar spacer 2 × M10 nuts 2 × Flexible joint bolt sets