Devon.
In regards to the Nissan Xterra, you need to decide if your upgrading the exhaust in an attempt to gain "Sound" or "Horsepower."
If your only interested in sound, visit a car club meet and listen first hand to what a variety of mufflers sound like on a V6.
If your wanting power, read on.
To be clear, many Xterra owners will search for more power by replacing the Y-pipe in our exhaust in an attempt to remove the factory dent and or choosing a cat back exhaust.
However, the truth is the factory Nissan exhaust (including the dented y-pipe) is not a very restrictive exhaust system.
I have seen dyno runs back to back with name brand exhaust systems on Xterras which showed single digit performance gains. You dont need to take my word on this matter as AFE advertises this fact on their own site.
Dont get me wrong, I feel AFE builds a top quality exhaust system and I applaud their advertising honesty.
From AFE : aFe Power is proud to introduce the MACH Force-XP 2-1/2” to 3” cat-back exhaust system for the 2005-2015 Nissan Xterra with the V6-4.0L engine. This cat-back system is constructed using 2-1/2" to 3” mandrel-bent 409 stainless steel tubing.
The smooth curves and increased diameter of the exhaust system helps remove power robbing restrictions and keeps exhaust gas flowing smoothly for increased horsepower and torque. In testing, this system produced a max gain of +5 horsepower and +6 lbs. x ft. torque verified by our in house dyno.
Obviously, Nissan designed a fairly good exhaust if AFE has attempted to increase exhaust flow with a larger diameter pipe, high flow muffler and mandrel bent tubing and can only increase an engines performance by such a small amount.
This is a minimal amount of gain for the website price of $599.00
People often claim performance they can feel, but this is often attributed to a louder exhaust and a tendency to drive more aggressive. The dyno dont lie.
Additionally, our intake is a cold air intake. It's totally sealed from the under hood air which is heated by our engines. Likewise, we use the same air filter as a Nissan Titan. To be clear, if this filter can support a 300+hp 5.6 liter V8, it can easily support the needs of our engine.
In my opinion, if your wanting power, purchase a Bullydog Tuner.
There is no better way to spend your cash and find proven horsepower gains.
In addition, the BD has a number of features which can not only enhance your peak hp, but also your partial throttle gains which better suits an offroad vehicle.