Wow!, that is so interesting! I have run LPG converted vehicle sine the 70's and currently have a Mercedes 190 with a unique, state-of-the-art LPG conversion. I think that it is the only 190 to have a variable output T.P.S. and full closed-loop system. I particularly like the mounting of the tank in your conversion! It still allows some luggage, etc., to be carried. Now, can you apply for a lower rate of road-fund? That is a big plus with the diesel... £30 a year!!!. What economy are you expecting? There is about a 20% drop in m.p.g. due to reduced charge density. If fuels were sold on weight and not volume, there would be no problem! I think that it MAY be possible to convert a DIESEL to L.P.G.! With a diesel engine, only about 35% of the fuel is replaced with L.P.G. This means that you would need a relatively small L.P.G. tank, so it would be even less obtrusive! I think that it would give the equivalent of a regular 70-75 mpg when running this type of conversion. You may have gathered that I am very technically minded... I have a Scientific background and love challenges! If I am told that "it can't be done", then I just love to think my way around it, and succeed! I feel that I would have the only Diesel/L.P.G. car, anywhere! Have you seen how cheap L.P.G. is in Holland!!! Residents have to pay a unique annual tax if they have an LPG car, but visitors don't! Please let me know your m.p.g. and qualifying for a lower rate of road-fund. many thanks, David