Take the engine as an example. It's a supercharged 1.8-litre four-pot, which makes a nice change from all the 1.6-litre turbos the GRMN's rivals seem to use. But actually getting it to fit into the Yaris's tiny engine bay was a massive headache.
And then there's the not inconsiderable matter of making the two components marry together on the normal Yaris production line in France. Toyota's global guidelines dictate a minimum clearance of 20mm in all directions between engine and body so that the motor slots in quickly and easily, keeping the entire production line moving freely.
Anyway, you get the point. The Yaris GRMN shouldn't really have happened at all. 'Every single day people told us this project was too challenging,' says Peeters. 'They told us to stop, but we always had the support of the management.'
Toyota is deadly serious about getting back into the performance car game and this project demonstrates that. The GT86, launched back in 2012, was a step in the right direction; the new Supra is on its way, and soon enough there'll also be a long overdue replacement for the MR2. After several years of being the dreariest, most spirit-crushingly earnest car manufacturer out there Toyota is becoming interesting again.
The supercharged four-cylinder will develop around 213hp (the car is yet to be homologated). Toyota's stated objective for the car is clear and concise: for it to be the lightest, fastest and most powerful car in its class. The body structure has been stiffened significantly and the springs and dampers are GRMN specific, while the front anti-roll bar is thicker. There's even a Torsen limited slip differential and four-pot brakes on the front axle.
The development programme still has a few months to run, but we got behind the wheel for an early taste nonetheless. As well as testing it on some of the difficult roads close to the Nürburgring we also squeezed in a single lap of the Nordschleife itself.
Then you notice the exhaust note. It's loud and rorty. Quite tinny, too. But it's entirely authentic, with none of the contrived pops and bangs that some hot hatches seem to favour. The engine itself is very good, for although it lacks the torquey punch of a turbo motor it's strong, it revs keenly to 7,000rpm, it's perfectly linear and throttle response is instantaneous. No turbo hot hatch can make that claim. The LSD allows you to get back on the power the moment the car is turned into a corner.
The six-speed manual gearbox is snicky and direct enough, meanwhile, and the steering allows you to place the car exactly where you want it. The chassis, however, is pretty uncompromising. The springs are fairly tough, which is where the car's poise and agility come from. There is just enough quality in the damping to deal with really broken, rutted surfaces, but day-to-day comfort could well be on the challenging side.
All of which is very promising indeed. No, it isn't a WRC car with carpets and yes, it is pretty expensive. But it's also as entertaining to hoof along a road or track as any small hot hatch you'll ever come across.
TOYOTA YARIS GRMN
Engine: 1,798cc, inline-4
Transmission: six-speed manual, front-wheel drive
Power (hp): 212@6,800rpm
Torque (lb ft): 184@5,000rpm
0-62mph: 6.3 - 6.5secs*
Top speed: 143mph (limited)
MPG: 37.6* (NEDC combined)
* subject to final homologation