Computer effects can be used in Mad Max 4 without hurting the movie.
If CGI effects are used to generate backgrounds, landscapes and small things like that I say its a good idea.
If its used to do whole car chase scenes then O NO NO NO NO NO NO NO! that sucks.
I'd agree with George using it to say do a car stunt that could be either very very difficult or dangerous then I say maybe use CGI
BUt don't do the George Lucas approach and do everything CGI