A few details I pulled from Bill's website:
"There are three differences between using this kit to upgrade your NXT and buying a new set.
- We don't include the sticker sheet, the new color sensor or NXT-G version 2.0 (the CD-ROM). Programs requiring the color sensor would have to be adapted to read grayscale values using your existing light sensor. As for the CD, LEGO has a very restrictive license prohibiting resale of their software. It's written so restrictively, you technically couldn't even include it if you sold your own original kit!
- Due to availability, the elements probably won't be the exact same color as ships with the official NXT 2.0 kit. I'll match them when I can, but there are no guarantees as to colors included.
- THIS KIT IS $200 LESS THAN THE PRICE OF A NEW NXT KIT. Why rebuy all the parts you already own?
If you purchase this kit, please let us know what you think!