Not heard of this one before either, I havent even heard great reports of lpg in petrol engines, several peeps have had problems.
As shifty said it wouldnt be too hard to make something explosive or at least very inflammable experimenting with this.
On a practical level im not sure how to inject the gas, it would surely have to go into the high pressure side of injection system and I cant imagine it would repay costs and you would need to carry lpg on board wit all the issues that brings.
Is ther a lot wrong with the power and economy of 300 anyway and if ther is why not make your own bio instead??