A lot comes down to personal choice. Those with lowered cars may prefer some more ground clearance by tucking the muffler up the back. When I got my twin muffler setup it was largely because I had a new fuel tank and a rear axle swap on the way, and wanted to see them on the car when done, didn't want extra exhaust and muffler in the way. And both of those kits still require you to select a set of straight tailpipes or splitter tips to add on. I don't recall any that went on without mods, a lot of cutting and shutting and relocating the hangers to where they should be.
If I had to do it again I'd get an exhaust shop to just custom make one, they had to anyway even with the kit. Even the RacePro mufflers, the quietest they offer, seem like they are going to be far too loud. Hasn't seen the road but shakes the garage walls obnoxiously. So if it ever got on the road I can see them being replaced as well.
