Why the limiter exists in the first place
Most German performance cars — Mercedes-AMG, BMW M, Audi RS, Porsche, VW R — ship from the factory with a manufacturer-set electronic speed limiter, usually at 155 mph (249 km/h). This is a gentleman's-agreement limiter, not a regulatory requirement in the UK. It exists primarily for tyre rating safety: the OEM Michelin or Pirelli tyres have a speed rating that matches the limiter, and the manufacturer doesn't want to underwrite warranty claims for tyre blowouts above that speed.
For track-day owners who have upgraded to Y-rated tyres (300 km/h), for private-land use, and for cars being exported to markets without the agreement, removing the limiter is a legitimate modification.
Slick Autos is based just off the M4 in Slough / Iver SL0, serving drivers across Berkshire, Buckinghamshire and West London.
What we do — and what we don't
We remove the manufacturer top-speed limiter via an ECU remap, preserving all other engine calibration. The limiter change is stored in the ECU flash and is reversible at any time. We do not touch emissions or diagnostic systems while we're in there — the car remains fully MOT-compliant from an emissions perspective.
This service is offered for track, competition, export and private-land use. It is not intended for, or marketed for, public-road driving. UK public roads have a 70 mph national speed limit — removing a 155 mph limiter is irrelevant for legal road driving, and we make that clear to every customer before the job.
We do not carry out speed limiter removal on commercial vehicles (HGVs, PSVs, light commercials over 3.5t) where speed limiters are a legal requirement under separate regulations. Fitting a speed limiter removal to a commercial vehicle is illegal and we will refuse the job.
Before you book
Two things we'll check before carrying out the work: your tyres must be rated for the intended top speed (Y-rated or better for >155 mph), and you must confirm the intended use is track, competition, export or private-land. If you can't check the tyre-rating box, we'll fit new rated tyres before the remap, or we'll decline the job. Tyre blowout at 170 mph is not survivable.
