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
Upgrade the exhaust note of your BMW M135i (F20/F21) with this Milltek Sport Road Rear Silencer. Available in three tip finishes, this EC-approved rear silencer is a direct replacement for the OEM rear box, delivering a notably more aggressive exhaust note with improved sound quality — all whilst retaining the refinement expected from a road-going system.
The Milltek rear silencer is engineered to work in harmony with the OEM front sections and catalysts, meaning no additional modifications or remapping are required. You'll notice the improved character immediately, particularly at higher revs, whilst cruising noise remains composed and comfortable. Choose from Polished, Cerakote Black, or Titanium tip finishes.
Fitment: BMW M135i F20 & F21 (Non xDrive models)
E-marked: Yes (EC approved)
Tip options: Polished (SSXBM957), Cerakote Black (SSXBM958), Titanium (SSXBM1025)
