I can chime in here. I actually have a set of the cans from the first exhaust system (wagon specific).
Not only that, but I also have the X02 (ebay), same as GMS, Mid and Y pipe.
As mentioned above, the tips of the muffers stuck out about 2-3" past the bumper on my sedan. The inlet to EACH muffler is also 3", making them impossible to swap out with the stock cans, or any other mufflers out there.
I ended up then getting a good deal on a mid and Y pipe from a member on here. This design of the mid and Y are the same as in the second exhaust you posted, except my mid pipe came with a resonator welded in.
Although the second exhaust system is only 2.25" after the Y, it is plenty. I have also heard that you can use the stock mufflers with this style (X02, GMS, eBay) exhaust.
I don't know what I'm going to do with the wagon cans. I'm over loud exhausts. I think ill need every bit of the stock mufflers and resonated mid to keep my catless turboback quiet...