You will gain some additional rwhp with a tune with just a CAI and cat back. However, I would wait until you do the headers then have some one that is very experienced do your tune. That way you will get the most out of your set up.
Do you think it would be worth it to get a dyno tune done on a car with only CAI and exhaust?
For those of you that have had it done, do you notice a big difference from the tune?