With money back guarantee, doesn't seem like there's much risk if it doesn't work.

http://www.performancechipsdirect.com/Nissan/Xterra/

I as well am very curious about this. Can it really be as easy as plug this thing in and get better MPG and HP?

I don't really know, hence why I asked.

On the surface it seems to make sense, but I would imaging that the Xterra's engieers would have designed it to achieve optimal performance between HP and MPG. That said, sometimes they dial things back to achieve a certain cost/price point.

Anyone have any true insight on this based on their own experiences with ECU performance chips/upgrades if not for the Xterra then in general?

I've done this on my mustang, and it made a huge difference. You can shoot for more aggressive timing and things to increase horsepower ect, and it's very simple and reliable. No different then rejetting and timing a carbed engine

http://xterrafirma.com/forums/viewtopic.php?f=29&t=8605

They have a different name for this chip everywhere but they are not going to work on an Xterra the way they will help on a mustang or any other chip ready ECU.

I didn't use a hard chip add on, I just got a flash unit and re flashed the ecu. I found that to be more logical

Interesting. I totally forgot about the Xterra Firma site; lots of great content there.

Of course something that sounds too good to be true (especially with automotive) usually is.

So it sounds like if you reflash the ECU it seems like you'll do more damage than good if you don't have certain mods done to take advantage of timing, fuel/air mixture ratios, etc?

I'm all for performance gains, but not at the expense [literally] of other things becoming an issue.

Sounds like this isn't an option?

Reflashing changes the way the computer handles the fuel injection and timing (if you have digital timing, I don't recall what generation you have). I have a CAI and catbacks on my mustang, and those with reflash added around 60-70 hp (to bring the thing to around 500 crank hp). It's been perfectly reliable ever since. I'd highly recommend it. If you don't like it, you can just reflash back! It only takes 20 min

There is a performance mod that can be done to the
ecu but it requires you to send it out and have it calibrated
to your tire size, weight, upgrades, performance needs and driving type. https://www.4x4parts.com/nissan/computer-upgrade-p-5542.html

its from 4x4parts.com and its 200+ and you lose your truck for however long. the v-plus module they offer doesnt reset the ecu but allows you to monitor the different variables and adjust your driving is what im told.

reseting or flashing the ECU is something im not familiar with but i know the Xterra ECU sucks to try to work on yourself or lots of guys would be adjusting for tire size, gears etc.... if you guys figure a way to change things without messing everything up - you just may be on to something big. Do it for less than 200 and without me losing my truck for 2 weeks and im in.

Usually, when you re flash in the performance world, if there isn't a program made up, you take it to a dyno and pay a fee, and they make a tune for you. I don't know if that service is under 200 or not, but it seems the best bet to me.