flat out 2days of very hard work,but i wouldnt recommend it cos to much can be rushed and if you make a mistake your knaclered,
but the best way of doing it is to mount your tank etc one weekend then you can still use the car next time you have spare time install lpg lines, then the following time you have off do the engine install and your still able to use the car, final part is the wireing, then you put a few litres of gas in the tank and check and check again for leaks, then the fingers crossed and park i a field somewhere and switch it over to ;lpg and see if it runs or goes bang!!!
by doing it in stages mate you can save yourself a whole lot of grief and you know exactly how its done, Have a man who will inspect the install and supply a certificate no problem!!
Omegatoy
If I started again (Omega) I would start with the ECU and basic wiring then off with plenum and fit cut injectors, straws, evaporator feed, then start on plumbing. with a Senator I'd start with front end water, then evaporator then LP gas hose and injectors, then front end wiring, then tank, then main gas pipe and filler, then rear end wiring, then cut injectors, finally the power supply.
Field - I had a good sniff everything was tight and while testing the pipework the **** thing switched over!!!!!! All outside the garage.
If you reckon £800 of petrol and that is the one use I would say don't bother. I cover enough miles to save about £80 a month