I bought a 2000 Lexus LS 400 last May and had it converted to LPG. Gas at the time was around 45p litre. I paid £1500 for the conversion and have found it to be well worth it. A trip to London (130 miles) costs around £20 at todays price - .63 per litre. I find it slightly annoying that the tank doesn't take anywhere near its capacity, usually only get about 25-30 litres into a 60 litre doughnut tank, but this appears to be because the pressure at the pump is low. If you fill up just after the (gas)tank at the pump has been filled you get a lot more in, up to 48 litres. Also the outside temperature makes a difference. Performance is hardly any difference unless the tank is very low, then the kick down doesn't respond so well, I usually switch the gas off temporarily, and back on immedately (just in case there is a hiccup). The added bonus is low emissions.