[AG454]

The first system goes all the way back to the axle, 3" all the way there. You mate it up to your factory pipes there, it goes down to 2 1/2" to match up. If you like the factory sound now then you will be happy. I had my car this way for a month or so before going to magnaflows and 3" all the way. The factory mufflers are a fairly straight through design, changing them is mostly for a more aggressive sound under acceleration. That second system looks like it mates up to the factory system after the cats, which means you will have 2 1/2" from there and the factory H pipe and not the ARH 3" X pipe. I would recommend the first system, I love mine, Easy install and quality workmanship. Good luck.