Clearly the only option is to treat it like an adventure game and use every time on him until we randomly hit on the one the developers thought would be handy.
I think you're right... So here's everything he has to say:
Aluminium Wheels:
:
Aluminium Wheels
Sports Muffler:
:
You know about mufflers, right? It's attached to the car
Super Grease::
:
Don't you know what grease is? It's oil that makes things move smoothly.
Pedal Converter:
:
This is like switching the accelerator and clutch
Road Dryer:
:
This provides the best grip on wet tracks. When using this, it is possible to The grip will be better
Road Wiper:
:
This improves grip on the ice course. It's the best thing to do
Kayo’s Photo:
:
Stop bragging, you idiot
Cute Masks:
:
If you wear something like this, people will look down on you.
Scary Masks:
:
This guy has a face that makes me not want to get close
Power Wrists:
:
This is something that trains the body. Wearing it will slow down your movements.
Bulletproof Vest:
:
It's a bulletproof vest.
Aconite:
:
This is a rhinoceros beetle, but it's a monkshood. Don't ever wear them together!
Vital Point Needle:
:
If you get hit in a weak spot like this I can't move for a while
Chloroform:
:
Hey, why do you have this?? This is a powerful sleeping pill
Cactus Thorns:
:
Ugh!!
Sandpaper:
:
That looks painful If you get rubbed like this...
Beef Jerky:
:
It's dog food
Hand Cream:
:
It also has insect repellent effect
Whip:
:
You're not SM, are you?
Earplugs:
:
Even if I can no longer hear the sound. Don't call to complain
Weird CDs:
:
It's a music CD.
Golden Cairo:
:
This hand warmer is so powerful it can even melt frozen ice.
Wig:
:
My acquaintance was wearing a wig. Go to the barber and get your hair cut. Apparently he had his wig cut off.
Reach Stick:
:
Well, it's a gambling charm. It seems to bring good luck
Interestingly there's a few here that sound like they're giving us buffs to make our chances better in wet / ice races - things like the Road Dryer / Road Wiper, and maybe the Golden Cairo.
The Reach Stick seems to be a good luck charm for gambling too.
I'll note that we have all of these equipped for the most part, so it's possible they're influencing parts of the gameplay as we go.