The new finding is that they won't pass through, but will merge. Will individual stars collide? Very few.
But this is a football board, so what about this:
The Milky Way, as it exists now, is a flat disc shape similar to a frisbee. Andromeda is more spherical. When the two combine, they will form an "elliptical galaxy," or what van der Marel described as a football-shaped galaxy.