I can measure the OEM ZX shock if you would like.......Happened to have one hanging on the wall.
The cobra shock will fit yes. It is bigger than the zx but still smaller than the s9 shock..
I used a s9 shock and needed to file away casing from the engine case shock mount to allow clearance for the shock... The shock rubbed the rear tire.
I'm THINKING you'd be ok with the cobra shock and not need any additional filing done.
If i am not mistaken the cobra shock is about the same length as the zx shock, it's just a bit thicker and prettier to look at...
The S9 on the other hand gave a 2" lift in the rear, which i love. No need for a riser with that one.