What is this thing i hear from exhaust shops?

I walk in and ask for exhaust 2.25 straight w/ muffler at end. And they ask me if i am going to Re-chip it after, something about my engine actually being detuned...

Have you guys experience that? what does that mean?
Please hit me back, is it something i NEED to do?

and what happens if i don't.

 

Truth be told it's something you probably shouldn't do unless you put serious mods on your car (i.e. altering valve timing, ignition timing, multiple throttle bodies or forced induction) because of the extra cost for minimal gains. He's talking about altering the ECU. There's absolutely no need and the benefits would be negligable without a good amount invested in other mods. If you do, you're probably better off going with a piggyback fuel system than anything else for cost vs effectiveness reasons.

 

As a side note to what Andrew said, if you find that the car isnt acting the same after the install as it did before, try simply resetting the ECU, and that should take care of any kinda of "issue"