Warped rotors are a myth. Most causes of that warped feeling stem from not properly breaking in the pad and rotor & poor pad quality (high dust). Mazda, like most Ford derived products, suffer from very dusty pad material.
Have a read. Very informative . I've used this link to help get my point across in the past.
Typing it takes too long.
http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
Cross drilled &/or slotted rotors are very hard to get resurfaced should the need ever arise. Best (and least expensive) bet is to use the stock rotor and a higher quality pad.
Have a read. Very informative . I've used this link to help get my point across in the past.

http://www.stoptech.com/tech_info/wp_warped_brakedisk.shtml
Cross drilled &/or slotted rotors are very hard to get resurfaced should the need ever arise. Best (and least expensive) bet is to use the stock rotor and a higher quality pad.