Originally Posted by Fabrik8

The S100 and S200 have the same tuning options, but the S100 doesn't have datalogging, g-sensor, and 3-step. The S200 has extra interface stuff, which is why it can do those extra things.

The S100 is just a copyright key that goes inside the ECU and allows you to use a ROM made with the Hondata software. There is a serial port in the ECU that the S100 board is connected to, and the Hondata ROM looks (over the serial port) for the S100 board. If it sees the board is there, it allows the ECU to work. That's the S100 board's entire function in life, nothing else. They're making money off of software, not hardware. The S200 works the same way but adds extra hardware functions obviously.
Crome is freeware, so it doesn't use anything like that. It's actually possible to disable the Hondata code that looks for the S100 board (so anyone can use the software), but I've never done it and I'm not going to do it, so don't ask. I've heard from reputable sources that it can be done though, and I'm only putting that out there to illustrate what the S100 board is used for.

Again, I've personally never done this, and I don't condone illegal activities that take money out of the hands of decent companies. Except Microsoft. Pay your money and support Hondata, or use a freeware program like Crome. Don't use Hondata as freeware.
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For normal use (i.e. not datalogging, etc.) the S100 is perfectly fine, and works exactly the same as the S200 for tuning.