Filming car interiors is hard, compounded by a lack of control over the environment and lighting. Here's a great video showing how to shoot car interiors the old fashioned way.
Back projection is one of those methods that is quite often now the butt of jokes. Anyone who has watched the Police Squad, and then the Naked Gun films will know full well how ripe the method of backscreen projection is for poking fun at.
However it has made a bit of a comeback in recent years with films such as First Man and Gravity using the process to great effect, eshewing the now normal green screen composite method. Just because a method is old, does not mean it is bad. Modern equipment and lighting techniques and knowledge can be applied to bring the process up to date. And if you are shooting a low budget movie, utilising back screen projection could be a way to provide for a very effective way of shooting.
We recently discovered this video, by Indy Mogul, which goes into the history and reasons behind the process, as well as showing a very practical example of how to set up lighting for a shoot using a studio and an $80 projector. While the results are not mind blowing, with a little more time and thought it could be made even more effective. What they achieved shows the validity of what they were doing.