Toyota Gazoo Racing development driver, Masahiro Sasaki, couldn't buy the parts he wanted. So he made his own - for you too

A trip from Manila to Kuala Lumpur is hardly an expedition. Finding room for it in Masahiro Sasaki’s schedule, however, is another matter.

Between racing, developing cars and helping other drivers get more from theirs, he has plenty competing for his time. Coming off a visit to the Philippines, it would have been understandable if Malaysia had been left for another day. We were rather glad he made the stop.

The occasion brought him to SC Custom Styling & Autopart in Setapak on 29 October, this time representing something particularly close to his heart: GROW Design, the aftermarket brand through which he develops parts he would want on his own cars.

GROW Design GR Corolla, as exhibited at Tokyo Auto Salon Malaysia 2026

Malaysian enthusiasts had received their introduction to GROW at Tokyo Auto Salon Malaysia earlier that month, through exclusive distributor Wing Hin Motorsports. Now, with SC Custom on board as an authorised dealer, Sasaki had come to personally sign and officiate the occasion.

Another flight awaited him a few hours later. Before that, we had a little time to talk about the cars, the parts and the personal preferences that had brought him here.

A racing driver's repertoire

The M Concept. Note Sasaki's name on the roof

Finding time for it meant fitting another commitment into quite a repertoire: team director and driver with GR Team ORC Field, development work for Toyota Gazoo Racing, Lexus, and Bridgestone, and racing with OTG Motorsports.

His day job has involved helping develop the GR Yaris and GR86. Years before that however (in his teens), the Iwate native trained as a mechanic—a background that gives him experience with the car on both sides of the workshop door.

GROW Design GR86

GROW brings those interests together. The business also handles driver development, race-car preparation and maintenance, but our opening question concerned something rather closer to home: his own car.

Having helped develop Toyota's GR models, why make aftermarket parts for them too?

His answer took us back to the GR86. He wanted his own aero for a car he had helped develop, but the available designs did not quite match his taste.

So he decided to make it himself.

“The starting point was thinking that, if I made it myself, I could make something that suited me best,” he said, in comments translated from Japanese.

An owner's wish list, with the rather useful advantage of being able to do something about it.

Built with care and attention

Sasaki explains to us his concept. Looking on is Evans Tang, who runs SC Custom

This work predates GROW's Malaysian arrival. Toyota displayed a GR86 with GROW aero, HALsprings suspension and a Fujitsubo exhaust at Osaka Auto Messe in 2022, and its own GR86 customisation material also describes Sasaki's approach as “normal plus alpha”. 

He returned to that idea during our interview.

“I think there are plenty of flashy aero kits. With mine, I'm aiming for something that looks really natural, like it's standard. Plus alpha. Normal plus alpha.”

There should still be plenty of the car you fell for underneath the additions.

GROW Design GR Yaris

But when developing an aero kit, what comes first: visual appeal or aerodynamic performance?

Sasaki questioned how often aftermarket aerodynamic claims are supported by data, then explained that GROW discusses its work with Toyota and carries out aerodynamic analysis. He wants to understand what an addition does to the whole car: its balance, its aerodynamic characteristics and even its fuel consumption.

His involvement also extends to drawing designs by hand, working with manufacturers and testing the results. He explained that GROW's Fujitsubo collaboration produces a different exhaust from the one Fujitsubo offers under its own name.

The catalogue spans diffusers, spoilers and other aero components, alongside suspension and exhaust products. Collaborations include HALsprings, Fujitsubo and seat manufacturer BRIDE. For someone buying into the connection with Sasaki, his role in developing the parts is an important part of the appeal.

The Morizo connection

It's a relationship that spans way back. This is a 2019 photograph, with Morizo (in front) and Sasaki behind him.

Making a car his own has also meant understanding what other people want from theirs. Sometimes, the person on the other side of that conversation happens to be Akio Toyoda.

Or, when the helmet goes on, Morizo.

Sasaki's relationship with Toyota's chairman has a teaching side. Toyota has documented the pair reviewing driving data and discussing their runs, with Sasaki helping Morizo improve behind the wheel. Its Nürburgring history also identifies him as the driving trainer filling a role once held by Toyoda's earlier mentor, the late Hiromu Naruse.

The pair is also pictured in this 2024 session, about the Lexus LBX.

That made us curious about the learning going the other way. What had working with Morizo taught him, and how had it influenced his approach to making cars?

“There is a great deal to learn from Morizo,” Sasaki told us. “I listen to his opinions and apply them to making cars.”

Those exchanges are part of development itself.

“The GR drivers develop cars while talking directly with Morizo.”

It was a glimpse into the conversations behind the cars, from someone who helps both develop them and teach Toyota's chairman how to get more from driving them.

His own garage interests, meanwhile, gave us another subject to explore.

Yes, minivans

Alongside applications for the GR Yaris, GR Corolla, GR86 and Subaru BRZ, GROW caters to the Alphard and Vellfire.

“I like minivans too, and I've owned and modified them,” he explained. “I thought it would be nice to have my own aero for them as well, so I developed it.”

The GR86 development driver has room in his affections for an Alphard too. His explanation was as recognisable as any owner browsing a catalogue: he wanted something he liked for a car he liked.

That enthusiasm surfaced again when we asked about other performance products—suspension, engines or exhausts.

Lowering springs and mufflers were already part of the work, he explained. On an Alphard, however, his preference is for a smooth rear end with the tailpipe out of sight.

Plenty of us would be wondering how prominently to display the exhaust we had just bought. Sasaki would quite like the Alphard's tucked away, thank you.

He is particular about suspension too. Some adjustable setups can introduce creaks and other noises, which he dislikes. He considers the original dampers well developed and sees value in retaining them while changing the springs.

GROW's published descriptions reflect that approach. Its HALsprings collaboration pairs springs with the original shock absorbers, with attention to ride comfort and handling. The Fujitsubo exhaust collaboration considers the sound, tailpipe finish and how the outlets sit against the bumper. 

More to come, for Malaysia and beyond

Sasaki sees room for a more sporting aero range, separating products suited to the normal dealer channel from parts with greater emphasis on downforce and sports driving. A name along the lines of “Super GROW Design” came up.

“I'm not sure about the name, though,” he quipped.

Alloy wheels are another possibility, with the same interest in creating a design of his own. Neither discussion came with a release date or a broader view of the products that are coming, but if the current products are any indication, expect more of the same neat-but-unique looks.

One man, many missions

There is a wider Malaysian role in that future, too. At the earlier launch, Wing Hin announced a joint venture with GROW Japan to establish GROW International as the brand's sole worldwide distributor. Malaysia has a part in taking the products to other markets, alongside making them available here.

On this visit, Sasaki had made time to personally officiate at SC Custom before catching another flight. After hearing how particular he is about the products, we appreciated him being there for the people bringing them to Malaysian customers.

Soon enough, he would be back on a plane. But here in KL, his designs would be staying on a little longer.