The reason I said it is because I've seen when the 4-2-1 design and 4-1 design are used and dynoed. I actually used both designs on my previous Hondas and I saw the big difference in the power band. I know you don't like Honda, but oh well....LOL. And I've seen the straight through design is usually on track cars. I'm not an expert on the exhaust system so I think JBrady might shed some lights on this.
As I recall, the tuners said the difference between the high pressure and low pressure with different designs can cause a different scavenging effect (more like a vacuum energy) that can help sucking out the exhaust gas at low RPM or high RPM. The result is the 4-2-1 with a few bends has more scavenging effect at lower RPM than the 4-1 design. However, at high RPM, the 4-1 is free to flow, while the 4-2-1 still has more backpressure. More details, I give up.