Hi guys n gals , I been running an Audi A4 1.8T for 3 over years now. With the price of petrol now - I m thinking of converting my car to bio fuel , i.e. - compressed natural gas and petrol. What with c.n.g. at half the price of petrol - I think the time has come. Only when I need the oomph shall I press the switch to change to petrol. Have you chaps know of anyone doing this ? Cheers !