I dont think it is necessary...just give the ECU a little bit of time and it will adjust to the new parts. If you plan on doing spacer intake exhaust and other breathing mods i would subjest getting a piggy back system of some type to make sure your fuel air mixtures are fine.

 

Intake/plenum spacer it's not critical. You can just do the battery thing to reset it. I think it's good enough for just a replacement cat-back exhaust too.

If you go with headers I would definitely consider a chip or reprogram, even a dyno tune to get the best out of them. Even with replacement CATS probably a good idea.