MR2 is a good performing fuel that is easy to tune. Steve125 posted some dyno results using MR2. Ultimate 2 looks like it might have some real potential. It's new enough that there isn't a lot of solid feedback yet, but I have a few friends who are going to use it in Aprilla 250 GP engines so I'll pass along any feedback they provide.
Forget about propylene oxide, it seems to hold some value as a combustion accelerator in really big bore engines with crowded combustion chambers like V8s, but IMO it's of little value for standard dirtbike applications. It's latent heat is fairly high so it provides some crankcase cooling in two-strokes. Air-cooled RD350s were a little bit faster at the dragstrip using 15% by volume. Keep in mind these engines tend to run very hot when pushed hard so any additional cooling of the crankcase tends to have a positive effect. The gains weren't really noticeable in normal riding situations riding around town in traffic. I think these types of gains would be much less pronounced on a water cooled engine, but I've never played with it enough to generate a lot of data on water cooled engines, so this just speculation on my part.
I'm still a bit sceptical about whether or not VP actually adds propylene oxide to CMP. I've never gotten a straight answer from them. They seem sort of tight lipped about what's in their fuel.
Propylene oxide is one of those compounds that seems cool and mysterious, but I think is best left to the alcohol funny car set. It can become extremely unstable if it comes in contact with rust, so storing or transporting it in steel cans is risky unless it is coated properly and the coating isn't compromised. It's my opinion that the risk outweighs any possible benefit.
If you do decide to play with it store it in plastic cans keep it cool at all times, and be really careful.
Bruce can probably give us some additional info on the dangers that come with it.
