Engine Tech: How to improve efficiency?

You guys went crazy on this thread since I was last here.

RX-7s Did they ever fix the tip seal problems with these motors? The version in the rx-8 was supposed to be better but I never heard anything more.

Another issue with transporting Hydrogen is that it will leak out of any tank.
Fuel cells are the only hope hydrogen has of being a viable alternative.

I thought they were using glow plugs (or something similar) to get hydrogen started in extreme cold?

jason