If its similar to Photoshop than a simple composite is very easy. First take your two pictures and make sure the two cars are far enough apart that they wont have overlapping features. Then Simply make two layers, one with each photo and delete the half of the top layer that is covering the car on the lower layer. If you exactly matched camera position and settings and there are no objects in the shot that move that might show the editing then it should produce a pretty decent shot.
