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Stone Exhaust
BMW M135i F20 F21 N55 valved cat-back exhaust AP504A
BMW M135i F20 F21 N55 valved cat-back exhaust AP504A
Regular price
£2,584.32 GBP
Regular price
£3,230.40 GBP
Sale price
£2,584.32 GBP
Taxes included.
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Direct-fit valved cat-back for F20 and F21 M135i models with the N55 engine - no coding, no adapters, no guesswork. OEM valve control integrates cleanly with your existing ECU.
- OEM-style valve operation: quiet cruise, full aggressive note on demand
- Zero drone thanks to tuned resonator and flow-optimised 7-axis pipework
- One-piece construction with crisscross welded joints for strength and consistency
- Includes Valvetronic remote (OBDII plug-and-play) for instant mode switching
- Validated for UK roads and climate - fits RWD, xDrive and LCI variants
Not a daily-driver compromise or a track-only shoutbox - it’s a fast-road exhaust that works as hard as you do.
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