On the first SL's Mercedes had some very long intake runners. They said it was because there was no other way to package the engine under the hood.

But that was just to keep the other carmakers in the dark about how the longer runners reduced the HP needed to suck in and transport air from the outside world to the interior of the combustion chamber. The increase in pressure generated by the actions of the intake valves was almost negated. Another way to say this would be: Less back pressure is a good thing.

Exhaust headers do the same thing: Reduce the HP necessary to push exhaust out. The shorty tube you are speaking of should work great since that exhaust is not leaving the engine by itself and the longer the exhaust system the more friction the gasses have to overcome to exit the system.

If anyone is unclear on the concept of friction losses in gas pipelines then all they need to do is visit a NG compressor station and notice the 1,000 HP motors that are used to push NG through the line.