I had both sensors replaced just to keep everything balanced by our village garage who have been servicing our family cars for the last 30 years. They replaced them with OEM. I think they were about £180 each. My Lexus has been converted to run on LPG the week after I bought her. I am paying around 46p a litre and I get around 17 MPG. She has never missed a beat and there is no loss power that I can feel. If you're thinking of getting yours converted be very careful who you get to do the install because there are more cowboys than good ones and it doesn't matter how much you pay for the LPG system if the conversion is done badly you might as well send me all the money and be happy with the thought that you have helped another LOC member to have a great holiday. There are lots of threads on here regarding LPG. You need to have a lot of patience, FSH or as near as possible is a must. Timing belt needs to have been changed and you need to see an invoice which is checkable. If it hasn't been changed then that needs to be taken into consideration in your negotiations. The only weak point is the Y section in the Stainless Steel exhaust which can be welded at a few independent garages for about £50. Be patient in your search there are still some great cards coming up but you have to be quick as genuine ones don't hang around long. One final thing, you may already know this but you can now check online for the MOT history, which is great to see what the how the cars fail and pass rate is and also a mileage check. Good luck with it and if we can be of help just give the forum a shout and we will do our best,