Would you save your knight in this sharp position or sacrifice?

h5 seems worth analysing.

I thought about h5, too. Haven't had time to really look at it, though.

h5 is mating if white takes on e5. 1..h5 2. fxe5, h4+ 3. Kh3, Nxe3# (3. Kg2, Qf2+ 4. Kh3, Qf3#)

White can just play h4 though. Nxd3 Bxd3 Qxd3 Qxb7 0-0 Qxc6 and white is better.

I also looked at e4, but black can play h4+ and is ok i think.

I think white is just better here, there just isn't enough compensation for the piece.  

Wow I found a very nice line. H5 H4, Nxe3! Fxe5( Bxe3 Qg4+, Kf2 Qf3 -+), and now there are many possibilities. please help my to find the best. One idea is to play Rg6 and another is to play Qg4+ Ke2, Qg2+ Kxe3 and now Maybe o-o-o looks dangerous. I am sure Nxe3 is winning somehow...

In the actual game, black played h5 and ended up winning on mate after a wild chase. So sacrificing the knight ends up being worth it!