Not sure that many people out there have this mod, and I'm not sure if I'm allowed to link to it in a ReadMe file, so you'll just have to find the car on your own for now.
The mod in question is the McLaren Senna GTR LM by RemZona, but the updated version by Ings_Z33 which among many other things, allows you to paint the car.
I started off by painting it white with red accents, but thought it would be funny if I put a few of the iconic design elements from the Mach 5 on it to turn it into a Speed Racer livery.
The map CM generated for the car sucks though, so only smaller decals were realistic. That's fine with me though because I prefer the more minimalist design honestly. Feels more realistic to what a customer in real life might do in my opinion.
Also added a blue driver suit so it looks a little more like Speed behind the wheel, without needing to change the driver model.
So there's a funny little experiment and hopefully someone out there can use this and enjoys it somewhat.
Also here's a link to the OP of the show, just to get you in the mood.
