In advance use cookie cutter to cut 1 circle cookie and ruler and knife to measure and cut two 1-3/4 x 4-1/2 in. rectangle cookies. Bake and cool.
In advance use royal icing and tip 131 to make 40 rose and 40 yellow drop flowers with tip 2 white dot centers. Let dry.
Ice sides and background areas of cake smooth. Outline car with tip 3 and fill in with tip 18 stars. Pipe-in bride and groom's head with tip 5 (smooth with finger dipped in cornstarch). Pipe in hair with tip 3. Pipe tip 2 eyes, mouth (smooth with finger dipped in cornstarch); pipe tip 5 nose. Fill in veil area with tip 3 and add tip 102 ruffle on top. Randomly pipe tip 5 bead hearts on cake top. Add tip 2 necks and bow tie.
Pipe tip 16 black zigzag on bottom portion of rectangle cookies and tip 18 white stars on top half. Lay cookie "tires" on cake. To make spare tire: Ice middle of round cookie white, pipe tip 2 gray line spokes and tip 16 black zigzag around tire; position on cake.
Pipe tip 1D band across tire and print tip 2 message.
Position flowers for bottom border and add tip 352 leaves. Tie ribbons on bells and attach to cake with icing.