A well-designed and tested full exhaust system can provide increased performance, power and speed. A set of slip-on mufflers is much less expensive than a full exhaust, and offers a change in sound and exhaust flow, as well as appearance, but not necessarily much change in performance. A full exhaust system requires much more skill (or cost if you are paying a shop to do the install) and effort to install, whereas a set of slip on mufflers can be installed easily using common hand tools.