Does anyone know the difference between a 3 1/2" and the 4" tailpipe versions?

I have a full system with 3 1/2" and it sounds deep and boomy while I know someone who has a full systems with 4" tailpipe and his sounds more crisp and WRC like!! I know this may sound daft but I was just wondering if anyone knew the difference.

I quite like the crisp noise!

Thanks
Mark


[This message has been edited by Mark Brown (edited 12 July 2001).]