Why is it that one needs a tuner such as the SCT? Seems like that since you can receive the tunes via email, why can't you simply plug your laptop into the port and load that way? I use a laptop and dongle to program downhole gauges (oilfield use) Seems like all one would need is the software. What am I missing here?

 

The software. Where you gonna buy it?

 

The flashers (tuners) are designed as a pass-thru device, tunes are loaded to the device and then loaded to the vehicles pcm. This is the most common method. A dongle is required to load tunes to the flasher with the SCT tuning software. The advantage of this set up is that an end user can purchase a flasher with tunes and be done with it for under~ $ 400 including "custom" tuning from a dealer. Or, you can write your own tunes using proprietary software like SCT's Pro Racer and load them onto the same flasher.... the price more or less doubles.
There is software available that will plug directly into the pcm via the obd port as well.