With SCT at least, you'll still use a handheld as a "middle man" between your laptop and the OBDII port. I use the XCal2 with the Pro Racer Package software on my laptop to tune and datalog my cars (along with an Innovative WBO2). This is the same software that your tuner uses when he/she writes a custom tune for your car. It allows you full access to the parameters of your particular EEC. However, if this is something you're not experienced with, it's quite easy to do some real damage with one little mistake in the tune. Tuning has a very steep learning curve.