I've been reading about all these different exhauts and their different designs, and I got to wondering: why doesn't somebody just make a straight pipe from the heads all the way to the muffler? Yeah, you could stick in a cat if you wanted to, but wouldn't a straight pipe be the most flow-efficient way? It'd probably be deafening, but I wonder how much better it would be.

Anybody with more knowledge than I care to elaborate?