I was reading up on that last year but never got around to hooking anything up. It's big with diesel applications and I think there was a a lot going on with it on the national DSM boards. Looked like a good solution to me. Propane has an octane rating of 118, it's cheap as hell and will also cool the intake charge like nitrous will, although not as much. The trick is to get a bottle setup that will allow you to deliver it in liquid form like nitrous.