That's not quite right. You can totally modify them. The restrictions are around what's allowed on public roads, not what you do with the car. (You can drive wh

That's not quite right. You can totally modify them. The restrictions are around what's allowed on public roads, not what you do with the car. (You can drive whatever you want on your land) And even then, many modifications are ok and you can get special classifications for "unsafe" cars (like vintage ones without any safety features)