I don't want to sound like a hater too much, it's great and I can see a lot of work was put into this, I can also see you took lots of inspiration from Level-R(also known as Project Torque, by invictus), but it doesn't suit LFS, in my opinion. Still an awesome demonstration though, the video is 5/5.
LFS should never have buyable tuning parts or paying for skins so you can use them, since it would just add unnecessary grinding to the game and raise the skill gap for newer players, because some people would have fully maxed out cars already. Also it would have aspects of pay2win if you would be able to buy these parts with real money.
S1 used to have a credit system, I remember winning against AI you would get 3 credits, I don't remember if this amount changed at all. XRT required you to have 300 credits. Being older I might have the patience to sit through the races to get to the faster cars, but it really was frustrating and I ended up hex editing the credits just to get there. And yes, I played S1 after S2.
You could basically do a "money hack" for this kind of system too, which kind of renders the ability of buying parts obsolete. It would require extra coding for the anti-cheat system to make things work as intended.
Definitely. That program was great, altough it allowed to completely break the wheels, too. But the best part of it was that it just edited the node points of already available wheels, and not import completely new models like the Pro Tweakers, that requires you to create your rim model and a texture for it.