String Theory Garage will be closed to the public from Wednesday, 29th July to Thursday, 6th August for our annual shutdown.
If you need to get in touch, please leave us a voicemail or send an email. Our team will happily get back to you when we return on Friday, 7th August.
Shopping online? Don't worry! Our online store will remain active! We hope to ship orders placed for in-stock items as normal during the shutdown. Anything else will be dealt with upon our return.
Thank you for your understanding, String Theory Garage Team
Maximise the exhaust note of your BMW M135i (F20/F21) with the Milltek Sport Non-Resonated Cat-Back Race Exhaust System. Louder and more aggressive than the road variant, this race system removes the factory resonator for a full, uninhibited exhaust tone that truly makes the most of the M135i's turbocharged inline-six. Designed for drivers who want maximum sound, particularly on track days or during spirited road driving.
A direct bolt-on replacement requiring no cutting or welding. Works with the existing OEM downpipe and catalysts. Available in three tip finishes to complement the exterior of your M135i. Manufactured from 304L stainless steel in the UK.
Fitment: BMW M135i F20 & F21 (Non xDrive models)
Race product: Yes
Tip options: Polished (SSXBM967), Cerakote Black (SSXBM966), Titanium (SSXBM1024)