Just so you know, the MSP springs you bought are designed to be used with MSP struts (kit part number 0000-8M-C14, ~$460). Otherwise your car will sit about an inch lower in the rear. This is because the MSP springs are shorter than usual, and the MSP struts have a correspondingly higher spring perch. I don't know why Mazda did it this way; it causes a lot of confusion around here. Some people have broken their end links with the setup too.
Another thing is that swapping out the front sway bar is super difficult. A dealership may charge you 5 or 6 hours to do it.