Only problem I would see with those is they are made for 3" axle tubes, which I assume the mazdas are not. That and they are drag race oriented so I don't know how well you could set them up for drifting. But I don't know much about drifting.
there is no kit
i have coil overs on my mazda. ready, take a deep breath, your gonna spend easy $1500-2000. thats only if you do all the work, cant fab and weld, add $2000. if your committed to dropping that kinda $$$$$ we will gladly help you with the details
here's the link to my build thread to see my setup