The presets are not stored on the tuner. The player software controls all of that.
The tuner pretty much just a "dumb device", the features are really all in the software. It's got some smarts, but not that much.
The difference between the kit and the original is: The kit has some extra pins for additional analog and switched I/O, to do project-type things like read pulses from an RPM counter, or to signal an external relay to turn on and off. However, there is no software to support these pins yet, so for now it's functionally identical to the original.
I'd heard talk about the kit's tuner chip possibly being weatherband-capable. I do not know if that actually happened or not. Anyone have that answer?