Render full object, or chop in half and use mirror modifier?

Hello,
I’m a Blender 3D newb, and I’m trying to model a very detailed car. So far, all I have is a mostly completed wheel rim. Long way to go…

Anyway, picture in your mind a car rim with 6 spokes. That being said, the top half of the tire is completely symmetrical to the bottom half. When I get to the rendering stage, particularly once the rims are part of the whole car, is it faster to have the whole rim modeled, or to chop the rim model in half, and use a mirror modifier for the other half? Is there any issues where the halves of the rim would meet?

Thanks!