Is this ship possible with 8.2 Million triangles?

How will the model be used? I'm sure if you have the modeling and texturing skills, it will be possible. You can use displacement maps for some of the details if this is for VFX. That would keep polycount lower at the expense of some extra render power.

If this is going to be a game model,try to keep the poly count as low as possible and if it's not then I think you can model as you like