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CSK Exhaust

CSK Exhaust Axle-Back Straight Pipe for BMW M140i F20/F21 (B58) – Backbox/Rear Box/Muffler/Silencer Delete Rear Section | 1 Series Performance Exhaust Upgrade | 304 Stainless, TIG Welded, 3.5in Tips | OPF/GPF Compatible | CSK002

CSK Exhaust Axle-Back Straight Pipe for BMW M140i F20/F21 (B58) – Backbox/Rear Box/Muffler/Silencer Delete Rear Section | 1 Series Performance Exhaust Upgrade | 304 Stainless, TIG Welded, 3.5in Tips | OPF/GPF Compatible | CSK002

£399.00
£449.00 £399.00
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Heads-up on cancellations & returns: if you cancel an order or return an item, you won't get back 100% of what you paid. We apply a 10% restocking fee, the outbound shipping is non-refundable, and we have to pass on Shopify / PayPal payment processing fees; these aren't returned to us when we refund you. International orders also lose on exchange-rate spread in both directions. If the original packaging is damaged or missing, a reboxing charge applies. For international orders specifically, if you refuse to pay our shipping invoice or supply a prepaid label after placing the order, the same deductions apply. We're upfront about this — please be sure of your purchase before ordering.

CSK002 Axle-Back Straight Section for BMW M140i F20 F21 | 304 Stainless | TIG Welded | 3.5 inch Tips | OPF and GPF Compatible

Give your BMW 1 Series M140i the soundtrack it deserves. The CSK002 axle-back straight section replaces the end silencer on the B58-powered F20 and F21, unlocking a deeper, more assertive tone and a sharper, sportier character at a price that makes sense. Crafted from premium 304-grade stainless steel and expertly TIG welded with full back purge, this tail section is built for longevity and clean flow. Finished with 3.5 inch tips for that purposeful OEM plus look.

We have run this setup on our own cars and installed it for many customers. Feedback has been consistently excellent, with owners praising the richer note, enhanced presence and quality of the fabrication. If you are hunting for a straightforward M140i sound upgrade that looks right and lasts, this is the one.

Key features

  • B58 axle-back straight pipe for BMW 1 Series M140i F20 and F21
  • Premium 304 stainless steel construction for corrosion resistance and durability
  • Expert TIG welding with back purging for strong, clean internal welds
  • 3.5 inch tailpipes for an OEM plus appearance and snug rear bumper fit
  • Designed to free up exhaust flow and deliver a deeper, louder, more engaging note
  • OPF and GPF friendly configuration
  • Part number: CSK002

Vehicle fitment

  • BMW 1 Series F20 M140i 5 Door Hatchback (B58) from April 2015 to present
  • BMW 1 Series F21 M140i 3 Door Hatchback (B58) from December 2015 to present
  • Compatible with OPF and GPF models

Why enthusiasts choose CSK002

  • Axle-back straight-through rear section, silencer delete, tail section upgrade
  • M140i sound mod that enhances tone and character without unnecessary complexity
  • High quality materials and welding for a product that performs and lasts
  • Great value alternative to full cat-back systems
  • Trusted by our team and our customers for fit, finish and sound

Manufacturing and lead time

Made to order by CSK Exhaust. Please allow manufacturing time prior to dispatch.

Professional installation

Professional fitting is recommended. MJ Modifications in Warwickshire offer in-house installation. For a fitting quote, email info@mjmodifications.co.uk.

Ensure the part is fitted by a professional. If the fit is not perfect, remove and return the item before starting the vehicle.

Compatibility check before dispatch

To confirm fitment for your vehicle, we run a compatibility check before shipping. Please provide your UK registration or the last 7 digits of your VIN at checkout.

Manufacturer and warranty

Manufacturer: CSK Exhaust

Warranty: 12 months CSK manufacturer warranty

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