HiI convert vehicles to run on LPG.Unfortunately your Honda has weak valve seats and you will get what is know as valve rescession which causes the valves to sit into the seats too far and cut the clearances down.This causes uneven running and poor consumption.The only cure for this is hardened seats which costs in the region of around £600.00.With the latest injection system available there is little loss in performance and consumption.The cost of a conversion is around £1250.00 +vat for a 4 cylinder to upwards of around £2500.00 for the more exotic.LPG is great but at the moment the gas suppliers are using the fuel /oil increase as an excuse to raise the price of gas as much as 9p in the last 6 months.Mr Brown has also seen fit to increase the duty on this "green fuel" so that in the next 5-6 years it will not be worth converting.By a Vauxhall Vectra or Zafira or Astra that has been converted by the factory as these are the best value for moneyRegards JC