I was wondering if it is possible as well as practical to change the stance of my Civic by lowering the rear slightly.

I was thinking a 1/2" lower in the rear might look nice,
but I don't want to go too low since I need to be able to drive in snow.

Are there any disadvantages to lowering the rear slightly?

 

Seems like that stance would be fine.

 

Don't think theres any disadvantage. You should be fine unless your exhaust is really low or something.