a question on legalities

[carratt]

Hi fellas
I just wanted to ask a quick question about something that one of my friends have done to their cars. They have stripped the back seats out of their mistubishi mirage and bolted a subwoofer to the floor. I was under the impression that this wasn't a legal thing to do but they are absolutley sure that it is. I just wanted to get your guys opinion on it
thanks
Brad