This may not be the best example, but think of it as this:

Think of all the piping that is routed to get water to your house. All the turns and connections. Now turn the water on, is there any issue with pressure? No, you'll have plenty.
This may be over simplifying, but the exhaust just needs to be pressurized. You could have the wierdest routing for exhaust, bolt a turbo on the end of it and it's still going to make power.
Hope this helps, just my opinion of course.

allen