[my first mustang]

No chips just a hand held device that reflashes your computer and plugs into your cars computer port located under the steering column on the dash. Takes about 5 min. to reflash and makes a BIG difference in the way the car runs & shifts. vmptuning.com has the X-cal for $379.00. As for the muffler shop question, probably not but GT mufflers are easy to find online for cheap money. Its not that hard to install yourself either. The silencer is the box that the stock air filter is in.