The cars you've seen on youtube are known as "VOB mods" where the VOB file of the car (which details what it looks like) has been edited to make them look like these other cars - they are the same as the standard LFS cars underneath. It's not allowed to discuss VOB mods on the forum as they're modified content but they are freely downloadable from a quick google search. Be careful that any mods you do use don't affect the collision detection system, which means you'll crash even though no-one has hit you.
Team Name: Need Dinner Racing Number of Cars Entered: 1 Car Numbers Requested: 69 Team Manager Real Name, LFSWorld UserName: Jack Atkinson, J@tko Drivers: Jack Atkinson, J@tko, England
ZOMG GUYZ - WE NEED TO REMOVE CUSTOM VIEW TOO COS THAT MAKES YOU EVEN FASTAR1111!!!
[slightly more serious]This pretty much explains why custom view is much worse than forces - you see everything you do in forces without the forces [/serious]