Yes, if you don't want to do it take it to a muffler shop and have them do it, if you trust them to.
If you are doing it, IIRC there are two take welds holding the Sti tip onto the pipe mounting brackets. You must drill those out ever so slightly. You can either cut off the brackets and install a new custom tip w/ tack welds or you can get a new tip, keep the brackets and tack weld on a new custom tip, or you can weld a new tip onto the existing pipe.
Good luck. I myself just kept the tip the way it was and I am fine w/ it.