Yea,
I'm no tuner. But I watch and listen for what they (the geek-tuners) come up with. After this last 3+ years of Tenere Tuning, I THINK this is the consensus:
Arrow Headers can give very nice results, but on their own, they can cause undesirable results.
But to get the very best results possible, you would need to go full-boat with an ECU flash, and PCV (or similar), and some nice maps.
Fortunately, at this point, you would get the benefits of loading maps that have many many hours of other people's efforts. These maps are a result of their dyno-time and autotune tweaking.
I'm sure there is far less total data on the 2014+ model. But I would expect that the requirements would be similar. Headers would require tuning.
I do know this:
(And I have stated it previously)
When there are about 80 or 90 Teneres around, you can definitely tell that a few of them have an extra snarly attitude when they crank up in the morning. And I don't mean just that their exhaust note is louder. There is more to it. When they blip the throttle, it has a different bark.
It's probably no coincidence that they are the same Teneres that have an inch or 2 of air beneath their front tire when they peel off for the days adventure. ::26::