TowRig.com - Diesel Discussion and Tow Tech

Can anyone tell me what Ford does when they"reprogram" the PCM? I would like my truck to run as strong as possible without heavy modifications. I plan on installing a 4" exhaust and a better intake and then drive the hell out of it.
Thanx in advance for your replies.

I would say they adjust fuel mixture and boost pressure other than that it would be hard to say as everyone ussually keeps there programs secret....