I'll try to answer some of them but, I'm no way an expert.
Are registrations Saved in the same manner as the 3k was with the extra step to save to memory so you dont lose your Reg upon powerup? same as T1
Can you save multipads to registrations?
yes
Can you save lyrics as text files/or to bring up during style play with reg?not sure
Can you use the black MS 50 Yamaha 3 pc speakers with T2 if you attach brackets if possible?not sure
What can you do editing wise with the USB connection from T2/PC?yes
Can you play Mega voices & S Art voices in real time?yes
How much better is the keyfeel then T1/3k?
much better
Is the Vocalizer the same as the T1/3k?
yes (crap)
Are there AUX Ins for Laptop or Mp3 player etc ?I think so but not near the board
What improvements were made to the Music Finder?Scott knows much more on that, I barely use it
How is the HD recorder? Multi track?it's a neat feature, haven't really used it much yet
Does anyone have the upgraded RAM chips is ther a noticable difference?I haven't noticed anything, it's mainly for the sample playback part
What size HD do you suggest?I have a 80 gig, prices are so cheap now it didn't really matter that much
I hope I confused you more