They allow for fine tuning
The AccessPort doesn't do that...
of the fuel/timing/boost curves to extract the
most hp out of your vehicle. They can also provide such things as launch
control, shift light triggers, nitrous solenoid triggers, etc, etc....
Nor does it provide for any of those...
Basically, they give you more than enough tools to blow up your vehicle if
you don't know what the heck you're doing.
The Accessport allows loading modified engine
operating parameters (collectively known as
"maps") that are written by Cobb Tuning. The
maps are user selectable, but the map content is
not---it's a "set it and forget it" deal.
The concept is to provide the end user with a
completed package that will render improved
performance and reliability, with minimal
attention & tweaking by the end user...not the
absolute maximum possible, but not risking the
engine, either...an analogy might be investing in
a S&P 500 index fund, versus making your own
picks of individual stocks.
Mo info at
www.cobbtuning.com
UTEC sounds more like what you're talking about.
There's a few others that allow greater
control/gains/risks, as well.