Size does matter...

A scale model is a representation or copy of an object that is larger or smaller than the actual size of the object . Well in our case the scale car model is much smaller than the real thing.

1:18 TOYOTA SPRINTER TRUENO GT APEX (AE86)

For me, most of my collection consists of the 1:18 scale model. Scale is an indication of relative sizes. A 1:64 scale diecast car is one 64th the size of the real automobile. In other word, the real automobile is 64 times larger. Likewise, a 1:18 scale diecast car means, the real one is 18 times larger than what you are seeing on your table top right now.

1:18 NISSAN SKYLINE R34 GTR 1999

In general, larger cars will be having more detailed, look more accurate and have more features...and ow...don't forget, more expensive too.