Here is a good pic of a Bi-turbo pipe
The more your stock pipe has that kind of shape the less difference you will notice.
If your stock pipe is shaped like a box or can... A Bi-Turbo will make a big difference.
And you can adapt any pipe with a shape and size roughly like that one and gain an improvement... but you don't want to alter the overall length more than 2 or 3 inches.
The shape and overall length are the 2 important things.
Don't forget they are louder also.