If the game is drawn, black wins; to compensate, white gets more time in the clock. Sounds fun.

White needs an extra piece.

and you think black would stand a chance if white had an extra piece? o.o

This isn't for serious tournament play of course, it could be used for gaining a more aggresive/defensive approach maybe. 

how much more time would white get 10min or more.

I think it is 5 minutes for White, 4 for Black, Black getting draw odds.  The original Armageddon time was 6-5, but it seemed that Black was too easily able to hold a draw in that time limit so it was shortened a bit.