[tx_zstang]

Listen if you want to, but if you're going to get them anyway, then go ahead.
You will NOT get 10 hp from shorties alone.
It will slightly improve the sound, but ONLY if you have different mufflers vs. the stock setup.
Drone is not caused nor cancelled by headers; drone is resonance in the pipes or mufflers caused by air flow waves which at certain pulse frequencies cause the surrounding enclosure (pipe or muffler) to 'resonate' with the pulsations.
If you are having vibrations from the exhaust, it's likely coming from the mid-pipe hanger supports at the rear of the transmission; that location tends to transmit vibrations to the body more than any other contact point.

The stock exhaust manifolds on these V6s are designed quite well and flow very good, especially compared to other vehicles and other years. Look at the passenger side: it's already shaped more like a header than an older-style exhaust manifold.

If you're looking for sound improvement as the primary thing here, focus on mufflers.
If you're looking for elimination of vibration/noise, look elsewhere.


As far as your shift points in the tune, changing a WOT value will affect when the shift occurs relative to speed and rpms. Lowering the value caused the shift to occur a little sooner, while raising it delays the shift. If you have times when a shift seems to 'hang' and not complete, then lowering that shift by 1-2 will help avoid that hanging effect.

Normally though, you want the shifts to occur at the higher rpms to stay in the power band longer. If you have a laptop, you can use your SCT to datalog the shift points and rpms. Do this and you'll likely see how much rpms drop after a shift, too.
I've used this approach to optimize my shift points for both street and track so shifting occurs at the best rpms while not delaying the shifting longer than necessary.