If you put the "Mazda" bar on, they won't cover it under warranty unless you upgrade the struts, because it states in the brochure that the aftermarket sway bars are intended to be used with the Mazdaspeed Struts. I would be very cautious installing the "Mazda" bar with the stock struts, because it is a solid bar and not a hollow one like the AWR.
Also, I'm not sure how the dealer is selling it, but usually when you buy the Sway Bar package, it comes with a new rear subframe. This subframe adjusts the clearance so that the bar will fit properly. This is why the AWR bar is easier to install...it comes with spacer brackets that just bolt up to the existing subframe and you don't have to change the whole subframe.
As for the front sway bar, there is a lot of work involved to replace that. You have remove the front crossmember, because there is not enough clearance to "snake" the bar out from the side. Most people, including myself, opt to leave the stock front bar alone. I have helped a friend swap one and it takes a good part of the day.