What are common symptoms of a warped brake rotor? Which aftermarket rotors are a good replacement?

 

The stock Mazda FD rotors are the best...

 

If they are warped, you'll feel pulsation when you brake, unless the ABS is kicking in. Usually, if you go on a freeway and cruise down hill, you can really feel the warped rotors shuddering. You can see if the rotor can be turned. Usually, it's better just to replace it bc turning them will make them below spec in some cases.

Stock is pretty good, I think you can get Powerslot grooved rotors pretty cheap too at about $90. I think the Rx7 store has some and you may try mazdaperformance as well.

 

Rotors usually warp, after you've run the canyon roads, and then keep your foot on the brake pedal sitting at a stop light...you trap the heat under the brake pad which is in contact with the rotor, while the rest of the rotor cools down.