Aesthetically, DX has side mouldings and a rear wiper. CX doesn't. All I know about the VX is it has 13" alloys that look similar to the HX wheels.

 

cx should have no moldings and no tach, but may have a mirror (mine does)

dx should have moldings, both mirors, rear wiper, intermitant wipers, and tilt wheel, and no tach, and a dead pedal (my buddy has one and i hate him for having tilt wheel and intermitant wipers )

vx has alloys tach and moldings

 

My 95 VX came with Tach, very light 13" alloys that are similar to HX 14" alloys, both outside mirrors, and a front lip.
It came without mouldings.

 

92 cx no mirror no molding no tach
92 vx mirror no molding tach
92 dx no mirror molding no tach intermidiate wipers and rear wiper
93 cx mirror no molding no tach
92 vx mirror no molding tach

thats whats on the ones in my driveway. when they were purchased

 

i wished i had the VX rims all i got is steelies.

 

A CX will never have power steering, but some DX's don't either (I've seen 2 that didn't and they were both 5-spds).

The biggest tell-tale sign if the engine codes are un-readable is to count the number of wires coming off the o2 sensor. DX uses a 4-wire heated-element sensor, CX and VX use a 1-wire sensor. A CX will not have power options in the interior aside from the brakes.

ANY model hatchback can have a passenger side mirror. It was a dealer option on all of them, but they came without them from the factory (unless it was an Si) so the original buyer had to ask for it and pay extra. The mirror's not a good way to determine the model.