Perfection, perfected: the JCR GR Yaris

27 January, 2023

Surely the feisty Toyota GR Yaris is nearly perfect? Our friends at JCR Developments weren’t so sure.

Toyota makes a small, rally-inspired hot hatch called the GR Yaris. You might have heard of it if you’ve been even vaguely near any car-centric corners of the internet, or the parking at practically any car event, in the last two or so years.

It’s one of those instant cult cars by virtue of being the sort of thing that doesn’t often get built anymore, and having a somewhat attainable entry price point (if you can actually get your hands on one).

It’s got four-wheel drive, a manual gearbox and 257bhp from a diminutive 1.6-litre, three-cylinder, turbocharged engine. It also weighs in at a fairly dainty 1,280kg kerb weight thanks to some tactical lashings of carbon fibre.

Straight out of the box, it’s a little streetfighter, an eager puppy dog of a car, with a remit that seems perfect for the often narrow, lumpy and damp B-roads of Britain. What more could you want?

As we’ve demonstrated before with their 911 GT2 RS, the answer is usually ‘quite a lot’ if you’re an engineer at JCR Developments. While Porsches are their bread and butter, they don’t deal exclusively in backward-engined cars from Stuttgart. When a performance car causes as much of a frenzied ruckus as the GR Yaris did on its 2020 arrival, it was only a matter of time before it rolled into the workshops of firms like JCR. The result is the car you see here.

JCR’s tweaks on this development car are focused more towards fixing the few negative aspects of the GR’s reception rather than out-and-out performance improvements. One of the biggest gripes amongst press and customers alike, for example, is around the standard car’s seating position. Sitting high up and bolt upright might help make the driver feel more like they’re piloting a genuine WRC machine, but it’s not exactly a favourable setup for most road driving.

JCR, as we’ve established in the past, tries to produce its own parts wherever possible, and that’s what it did with the extra low seat frames in their GR Yaris. To complement this drop, the engineers discarded the standard front seats – perfectly nice if slightly bulky buckets – for a pair of Recaro CSs, a long-time stalwart amongst road-biased sports seats.

Another common grumble? The soundtrack. A three-cylinder should make a uniquely offbeat, throaty rasp, but from the factory it’s a bit… lacking. This isn’t really the GR’s fault – all modern cars have to adhere to an increasingly strident set of rules regarding noise. It’s still a disappointment for many, though, which is why JCR’s development car is fitted with a silenced titanium exhaust system (developed in-house, naturally). This unlocks a bit more of the engine’s character, while still making sure the car doesn’t fall foul of track-day noise restrictions or make your neighbours want to throw eggs at it. At the other end of the car, an ITG panel air filter uncorks some more induction noise, and, together with the exhaust, provides a subtle bump in power.

One thing that never really garnered much criticism was the handling, but the JCR team couldn’t help themselves. An adjustable set of custom Eibach springs, engineered just down the road from C&M by the brilliant minds at String Theory Garage, bolts straight in in place of the originals. This gives the GR a smidge more agility through the twisty stuff, with the side effect of making it sit deliciously low, like a rally car set up for the glassy tarmac stages of Spain or Japan.

Finally, JCR has turned its attention to the round things at each corner. The standard Michelin Pilot Sport 4S tyres have been swapped out for the more aggressive, track-focused Pilot Sport Cup 2. They wrap a set of Enkei RPF1s, something of a design classic amongst alloys, and handy reducers of unsprung mass.

For many, the Toyota GR Yaris is close to the perfect car. JCR, though, have taken some subtle steps to make it…erm, perfecter.