Performance Chip
 

Looking at buying a performance chip for my 2014 mustang gt 5.0 , not sure which one is the best for adding more horsepower

TUNER, not a chip...

The "chips" are simple cheap resistors to trick your MAF and other sensors. And you pay too much for the 50 cent resistor.

To safely add power you need to get a tuner like SCT which adjusts the computer parameters.

OK, here's an imponderable. My vehicle, 2004, has been showing code for "HO2S Heater Resistance Bank 1 Position 2 for longer than I can document. Everything so far has been a strike out, even including new wiring and fusing to the heater and PCM. Of course, sensor was replaced, twice, even though the original sensor's heater resistance was in spec, and no resistance to ground. Eventually, I've learned that code is used by Ford to indicate Cat malfunction. Vehicle runs perfect.

Have you numbers to tell me what voltage that sensor should be putting out to the PCM, and if so, can I check sensor output with my code reader? Certain I can, but how to add resistance to the signal circuit either in series to lower the output, or parallel to increase it, depending on which way it needs to go? To do that, one needs to know the signal current......New cats are $600+, lotta dough to clear a CEL, and I'm YET not convinced that'll do it.

Thanks for reading and thinking about it.

JimC; there are "chips" that work, they're just dated... I don't consider wiring to an AIT sensor
a chip... There are actual chips you could buy that go between ECU harness, like sandwitch
in between. Tuners program through the OBDII port, they make dongles that tune on the
fly, it uses a chip to change parameters without programming the EEPROM in the ECU.

JET still makes these for the Mustang, an in-between the harness device:
https://d2hw29brqn7o70.cloudfront.ne...t-70110_48.jpg
This is not a simple resister, these work, but they're expensive, and not programmable.
They work by changing the data sent to the ECU, so it can increase air and fuel, and timing.
The 70502 is V8, and 70501 is V6.

On my VW, I had a box that plugged into the MAP and BOOST sensors, and you could
choose +4 or +6 boost setting, it uses a CHIP to modify data to the ECU. This added
up to 45 horse power, with regaped plugs, and 93 octane fuel. It did nothing but send
false readings to the ECU so it could increase boost and timing. Was wonderful, and
made it a whole new driving experience. At idle, it used OEM values as to not effect
idle. The ECU still handles all the parameters, but bases on what the sensors were
sending it, but through the box. The module has two "Y" connectors, one goes to the
sensors, the other to the ECU. Same basic principal as that JET chip, it is simply
a go-between to fool the ECU into more boost, fuel/air and timing.

These devices change what the ECU sees from sensors, so it adjusts parameters to
make more power.

That JET type chip was all that was available before Tuners came out. Now that there are
tuners, there is no reason for the JET chip, unless they're giving them away.

VWs tuners are even more expensive, so the boost module is a 50% cheaper route. I had
one in my former '15 TSI, and it works, wonderfully. I beat V6 chargers and 4.0 mustangs,
hands down. I gave GTs a run, they weren't expecting 210+ HP from a 1.8T Jetta... It was
so much more fun to drive. If they could make a module like this for the Ecoboost mustang,
it would be wonderful...

Being that you are in Cali, No. Most "chips" are just resistor based devices that fool the PCM into running rich.

Get a tune from a reputable company and just ask for a tune that is California friendly.

Since you live in California, you are just playing with fire trying to alter your engine's performance through chips or tuners or anything. For such a "car" friendly state, home of hot rodding, blah, blah, blah, you couldn't live in a worse place to fool with emissions from trying to alter your stock tune for a few horsepower IMO.