While exploring the Mustang case i saw that a lot of hatch ones are classified as coupe ( might be same for Celica ) and some others as hatchback. I do understand why we get for those two cars a different classification depending of the model but should we fix all the hatch Mustang ( and possibly Celica ) as hatch ?

Speaking of the case , i suppose that Integra, Probe, Tiburon and similar hatch-opening coupes are classified as coupe due to the shape of the rear , that goes on a slope instead of closing straight like a VW Golf for example, am i right ?

I think it would depend on how it was classified in the brochures ? No ?

I know night cub did some research in the past on other models 2 door sedan vs 2 door coupe. He might have some insight?

I think it would be useful to separate them for models that offer more than one two-door bodystyle, like the Mustang, Celica and Nissan SX models. For cars like the Probe, 3rd-4th-gen Camaro/Firebird or Scirocco, it's not as much of a concern.

The only one where it would get tricky would be the Geo Storm, which had two different 3-door models. I guess also the AMC Spirit/Eagle SX4 also had an issue with the slopeback and kammback versions.

i agree . If no objection i'll start slowly with the Mustang

How will you do the change? Visually is it easily possible to tell them apart?

This makes me thing to the Peugeot 104, launched as a 4-door sedan:
https://en.wikipedia.org/wiki/File:Peugeot_104_1974.jpg
and changed to hatchback in 1976:
https://en.wikipedia.org/wiki/File:Peugeot_104_GL_(15436439521).jpg
Not easy to tell them apart

that 104 is quite a challenge !
thankfully, the Mustang is easier
coupe : http://images.gtcarlot.com/pictures/39676218.jpg
http://images.gtcarlot.com/pictures/39676226.jpg

hatch : http://images.gtcarlot.com/pictures/6444798.jpg
http://images.gtcarlot.com/pictures/6444808.jpg

Also, there was no GT coupe, they all were either hatches or convertibles ( except for 1982 when Ford re-introduced the GT but did not officially had the convertible back yet, it came for 1983 )
SVO ( 1984-1986 ) and Cobra ( 1993 ) are also hatches only

i'm not too familiar with the 1974-1978 gen so i'll have a closer look before changing anything

Similar goes for the Celica and Nissan SX as night cub suggested ( both, if i remember offered all the versions in both styles )

There is also a possiblity that most of the Celica are already classified since they had the Liftback name in extra field

Last, i won't change any that does not offer any visual difference ( big close-up of the front for example )