Release date of the full game will be approximately around spring 2013, so multiplayer and demo will for sure come within a year's time from now... (significantly earlier than S3 (I bet!) /sarcasm)
I got it for a week now and don't want to give it away ever again!
A quick google, wikipedia or reading the news right out of the trouser pocket is really cool. Not to mention letting it recognize a song playing on the radio, and countless other little apps that are availlable for free...
1. paid 100€ (senior membership)... not too much for getting weekly updates for the next >2 years until release imho (but game is still at alpha stage!)
3. kart feels quite good atm, got shifter karts as well, not as good as in 'kart racing pro' but they're closing up there...
4. very detailled tracks indeed, new updates of all tracks coming constantly!