I've had several mustangs. Never used a performance chip. Anyone have any advice on them?

 

The S197 and pretty much all modern cars no longer use "chips", you just reprogram the computer with a tuner device. There's pretty much SCT and Diablo, but it's more important to choose who you want to write the tune before buying a tuner, since they usually only do one or the other. For "mail order tunes", I'd look at Brenspeed, Bama (American Muscle) or Lund (sold through Lethal performance).

 

I bought the sct4 tuner from American muscle and get my tunes done threw bama performance, good people awesome service and I can't complain about the results would fully recommend them

 

The newer cars don't use 'chips' like the older versions. You need a handheld tuner, and the SCT is the most commonly used one by the tuning companies.

If you are talking about the ebay "chip", that is just a 50 cent resistor that tricks your MAF - not exactly tuning and presents a danger to your engine.

 

No ebay chips that's a disaster waiting to happen. Make sure to get a custom tune from one of the companies listed dyno tune is best but mail order is fine for most N/A setups. The dyno will yield more horsepower as they can tweak it for local conditions and engine condition since no two are exactly the same. But money wise cant go wrong with a mail order from a quality tuner. I have the BAMA performance tune on mine but will probably go back to the street tune from them. Its fun to drive but the throttle response is a bit much for daily driving you really have to watch the clutch in traffic.