I wouldn't want to mod our ECU... It's screwy enough as it is.

As for Octane boost-
Over the shelf ones are weak, but lubricate your engine well so they're pretty much safe but useless. "Techron" and "ProPower" are octane boosters which consist mostly of MTBE I believe...

I live in SoCal where "Premium" is now 91 octane. ($@#^ckers) I've messed with using Toluene - a paint thinner I bought from Sherwin Williams. It doesn't lubricate the engine well, and may deteriorate my fuel lines... but hey it's like 114 octane Xylene works too, it's 117 octane. MTBE is 118 octane.

All I can say is the car is somewhat more responsive and powerful in the midrange, and I get less detonation under boost. Definitely would use it to road race, but definitely not daily.

BTW- Use at your own risk, you stand a good chance of blowing yourself up, getting very sick, and/or killing the planet.

http://www.vtr.org/maintain/gasoline-octane.html
http://home.earthlink.net/~galiagante/house-booster.html