To add to Doubie's reply: For $150, I had a local speed shop tune my PCM to turn off AFM, turn off the rear O2 sensors (for catless long tube headers), remove the speed limiter, reduce Torque Management and tweak the transmission shifting a little.
I recently ran across a guy (
>CLICK HERE< ) that will turn off AFM for $50. Your car will be off the road for a few days 'cuz you mail him your PCM. But, for that inconvenience and $50, you may greatly extend the life of your motor. If you later decide to
delete AFM (replace the components with their non-AFM variant) to essentially bullet-proof your engine, the tuning part will already be handled.