Exhaust choices are very personal, best bet is to listen to them all, there are many sites where you can listen to the different axle back systems. That is the other question, I assume you are talking about axle back only and not also replacing the H pie with an X pipe. Replacing the H section will require cutting of the factory exhaust. Replacing the axle back section is pretty much an unbolt and bolt on, with a couple of caveats, you need to be able to lift the rear of the car high enough to remove and re-install the sytem without cutting, unless the new system you get has the over axle pipes in sections (some do). Also, I have personal experience with the muffler hanger bolts, they will push up into the frame, where you cannot access them without removing the rear body facia - if you are not careful. If you remove the bolts, make sure you rethread at least one nut, on one side, because they are actually a U style bracket that protrudes through the frame. The following URL will give you step by step instructions -http://www.corvettefever.com/techarticles/153_0410w_chevrolet_corvette_c5_exhaust_upgrade/index.html
Hope this helps...Mark