I bought this car for 2500 from my friend's dad, and it had a bad tranny, bad brakes and rotors.
Since then I've had to replace the timing belt, water pump, and mass airflow sensor.
Just like all MX6's, my sensor went out, although which one I do not know. It went bad, and it felt like I had VTEC, which was not good.
Also the infamous pinion problem.
All are fixed now, and it's running smoothly.
I love this car, and would like to turbo it one day.
So far I have bought cold air intake, 21/2 Magnaflow cat-back exhaust, added ground wires, new vacuum hoses, high performance gaskets, headers with a down pipe, light weight flywheel and crank pulley, stage 3 racing clutch, short shifter.
I took the leather back seats out and stripped the interior. The only thing I have is one leather driver's seat, I couldn't throw it away, it's too comfortable.. weird I know...
I have the Mazdaspeed lip kit and side skirts.. don't worry, it's not anywhere near the ricer Invader kit.. I just added the big brake kit, and it came with drilled rotors; it's a lot smoother.
I kept the stock size tires, and got light weight 15 inch rims.. The tires are great; they are BF Goodrich racing tires.. very nice.
When changing the gaskets for kicks, I painted the 2 valve covers blue, and the engine itself black.. I will try to get pics up soon.
All in all, a very great car, and was worth putting money into. Watch out for the pinion problem and the steering problem, and also the sensor. Mazda is the way to go.