TOYOTA GR YARIS (Mk4)

Most owners start with a cat-back exhaust for sound, a panel filter, upgraded brake pads and fluid, and a modest set of lowering springs. A remap is the biggest single performance gain and is typically paired with an uprated intercooler for heat control. The standard chassis is very capable, so avoid cheap coilovers and focus on brakes, tyres and cooling if you plan to use the car on track.

Stage one maps on the G16E-GTS typically add around 30–40PS on standard hardware, with more torque in the mid-range, according to published tuner figures and owner reports. Further gains usually call for a sports-cat downpipe, an uprated intercooler and better fuelling. Results depend on fuel quality and the tuner, so ask for dyno data from your own spec rather than relying on headline numbers.

Some do and some do not. The 2024 car has a revised front end, a new rear lower garnish, changes to the chassis and an automatic option, so bumpers, splitters, diffusers and some exhaust and intake parts can differ. Engine service parts and many brake parts carry over. Check the fitment notes on each product, or save your car to My Garage so only compatible GR Yaris parts appear.

A moderate set of lowering springs, such as Eibach's, tidies the wheel gap and lowers the centre of gravity while keeping the factory dampers. Keep the drop sensible, because a big drop can affect bump travel and ground clearance on UK roads. Have a four-wheel alignment afterwards. Circuit Pack cars already have firmer suspension, so check the spring listing suits your version.

For track days, a fast-road or track pad from EBC Brakes or Pagid, braided brake lines and a high-boiling-point fluid such as MOTUL RBF are the most effective upgrades. They reduce fade and give a firmer, more consistent pedal. Bed in new pads properly, bleed the fluid before each event, and check pad depth between sessions, as the GR Yaris can use pads quickly on circuit.

Fitting aftermarket parts does not automatically void a UK warranty, but Toyota may refuse claims for faults it can link to a modification, and ECU remaps attract the most scrutiny. Toyota's Relax extended cover also relies on servicing in the Toyota network. Keep records of parts and fitting, discuss plans with your dealer, and declare all modifications to your insurer. Our team can advise on mods that stay close to standard.