Put a "Shell" modifier on each letter to flesh it out and you should get something like what I have in the picture.
It looks good but the letters are flat on the front and I think it would look better with a bit of a bevel to catch the light. Collapse the stacks of the letters and convert them to editable polys. Let's start with the "P" and use the bevel tool. Select the polygon on the front of the letter and then select the bevel tool. The picture shows the settings I used. Do the same for the remaining letters. Use the same bevel settings for each letter. Now the letters will catch highlights nicely. Group the letters together. Make a duplicate of this group and hide it. We will need the letters again later and it would be a pain to have to make them again.
Place the letters on the dashboard as shown on the dashboard. Also add two boxes, one above and one below the letters as shown. It's advisable to smooth the dashboard before you do this so you can place the letters more accurately.
Now that we have the letters drawn, we might as well unhide the duplicates we made earlier and place them on the front and back of the car. Let's start with the front. Duplicate the letters and place them as shown just below the bonnet and create a box to place at the bottom of the letters. Group the letters and the box and apply a bend modifier to them. Now tweak the bend settings so that the letters bend around the front of the car. Don't forget to smooth the body of the car so that you can place the letters accurately.
Do the same for the back of the car. Duplicate the letters from the front of the car and rotate them 180 degrees. Adjust them to fit at the back, just below the trunk.