PHP GET variables

My URLs are currently way too long, so I'm thinking of using index.php as a redirect to other parts of my site. What I had in mind is www.example.com/?nigger. The thing is that I'm using free hosting (inb4 shitstorm), and I have to change hosts once in a while. Are there any server configurations (which support PHP at all) that wouldn't work with this?

Given that you're using index.php:
www.example.com?stuff
www.example.com/?stuff

...or a.php:
www.example.com/a?stuff
www.example.com/a/stuff
www.example.com/a.php?stuff
www.example.com/a.php/stuff

As far as I know, all six methods should work. Would any of these fail with certain servers?