Learn Spanish (Latin America): El carro rozó la pared.

No, rozar means to graze, brush against, or scrape lightly. It implies the car just barely touched or scraped the wall as it passed, rather than having a full collision (which would be chocar).

Since rozar ends in -zar, shouldn't there be a spelling change to -c- in the preterite tense?

That spelling change from z to c only happens when followed by an e or an i. You see it in the yo form: rocé (I grazed). Because the él/ella/usted ending here is -ó, the z stays exactly as it is: rozó.

Could I use muro instead of pared for "wall" in this sentence?

It depends on the type of wall! A pared is usually a standard architectural wall, like the side of a building or an interior wall. A muro is typically a thicker, freestanding outdoor wall, like a stone barrier or a defensive wall. If the car grazed the side of a house or parking garage, pared is perfect.

How would I apply this lesson's topic to say "I wish the car hadn't grazed the wall"?