My WRX Wagon is LPG'd and stage one remap 280BHP
Have been running LPG on my camper van for years so this was not anything new to me. My spare wheel sits in a cover behind the passenger seat, doesn't bother me. Mine was not done by Simon, it was done by Dougie Martin in Glasgow.
45 litre tank fills for £24 odd and gives me around 220 miles of spirited driving, when the car was remapped i just turned the LPG system off. The LPG kit then got remapped for £15. The LPG kit also needs a annual service and new filter £30 all in.
Normal driving you just don't notice the difference, hit the button and it turns back to petrol on the move with no issues. I plan to keep the car, but regardless the LPG kit puts a smile on your face when filling up :-)