What is the difference in a Neon and a Neon Highline?

Highline was a trim level option.

The engine size was optional SOHC or DOHC 2.0 (the DOHC was the better) it was available in a 2-door or 4-door version.

Here are the main advantages of a highline over a base model (items listed as optional were not available on base models):

A/C was standard,

power windows and locks were an option,

tilt and cruise was available as an option,

Rear window defroster was standard

Optional tachometer,

dual remote mirrors were standard, power was available,

body side moldings (moldings on the doors) were standard

There were other options and standard items as well, but those are teh main differences.

In 1996, the model line went from "base" to "Highline" up to "Sport." The "sedans" all had four doors, the two-door Neons were called "coupes." Manufacturers introduce these models to give the consumer the graduating option of choosing less to more expensive. Excepting the plethora of options available in all models, the differences in these levels were minor. The most basic of the base model for example did not have A/C, a sound system or automatic transmission Although they were optional. It did have a cheap, plain interior and basic wheel covers. My '95 Neon Sport had standard fog lights and body-colored door handles which were not available in the base or Highline. However, all models had the same base engine and base transmission.

The regular neon has a 2.0 Sohc head, one cam, The highline has a 2.0 Dohc, 2 cams. and I think they are 2 doors

I'm guessing it could be one or the other...or both.

Try looking it up on Kelly Blue book (.com), should give you the breakdown of option packages, etc.

It was a trim change, though I'm not certain what options were included.