That's what I mean Madman, glad you found that out too.But first you need to buy the car in career mode don't you?
I remember I added a button in the car1.mnu that says:
nextmenu=Cr_garag (so you can quickly switch between singleplayer and career)
In Cr_garag.mnu I created a button to go to car1.mnu.
And using objecttype=11
When you purchase a car in career mode, and upgrade it to whatever level, you also have this car visible in singleplayer.
But like you said in ''race'' the car has no upgrades.
The reason you can't change color is because you bought the car in a specific color.In career you can't change color either.
Funny thing is when you select another upgradeble car in singleplayer you also get the upgraded version .
You need to go to another menu, and than go back to player car menu to see the car displayed.That's the problem with objecttype=11.
It's because the object type is car-agnostic so it'll always look for upgraded car regardless of which car it is.
What would've been really neat would be CAR1ENG.BNK, CAR2ENG.BNK, and so on, to replace sounds of upgraded cars. It was not beyond their capabilities, but they chose not to do it. Same with dash upgrades.
Still, what you guys are doing is making the game show a different model in the menu. Getting the game to load it in the race is a whole different thing. It may be impossible without editing the executable, but I suspect it wouldn't be as difficult as some other things like changing folder of traffic cars, increasing number of available serial numbers, etc. It's possible to affect the car mesh in the menu and have the effect translated into the race, via the Convertible option, but the game was programmed to expect such change, and there may be numerous instances of it in the code because of the weather.
There are many things that may have been cut from the game engine. The nomenclature of CAR00.TGA is no accident, there were rumors that it may have originally been possible to assign more than one texture to each car. Would make modding incredibly convenient because 256x256 maps are no joke for a game of that era if the maps are used for car parts rather than whole body. But NFS3 (which, to my knowledge, is where it first appeared) came out at a time the bulk of the video cards could barely cut 16MB of video RAM, so the single texture system was easier to implement. This would require further modification of the graphics engine, which is not the goal of VEG's project.
It would be easier with the source code but, judging from VEG's reports, it seems even NFS3 is many steps above something such as Doom or even Quake in terms of complexity. EA isn't interested in releasing it, not viable commercially (they don't even sell the game anymore) and even without Modern Patch you can play it on different OSes, so there's no need to port it.