Nice thing about a SCT chip is that it goes in the service port and when (if you ever need to) unplug it, the stock program takes over again. Plus, you won't have any down time should threre be any problems. This chip will allow (w/ the right program) allow the EEC to adjust timing when needed. I have a SCT w/ my KB and they adjust timing w/ this. And to answer your first question, both. Get a SCT chip and have it dyno tuned, you will get the most out of your car. Be careful what shops you go to, the comment about re-flashing so you can adjust your timing sounds sort of hairy, you can do that w/ a chip, some will try to rake you over the coals. Good luck man.
