I am thinking of camming my 2007 pontiac Grand Prix N/A with the L26. The problem with that I am hearing is it will need a tune. Which I am fine with. My question is that since it's an 07 would I have to change to a 04-06 PCM? If I do change the PCM what is different? Will it change my driver information like my odometer? Will I need a different wiring harness?