funky, i'm sure you will have many a person giving you their two cents,
however, read my thoughts
every man and his dog now wants their car converted to LPG with the gov't rebate, supply and demand concept ensues that fitters of LPG tanks will (and already have in WA) raised their prices to compensate for the gov't rebate and to counter demand with limited supply to the tune of about a $1500 add on to the previous cost,
all fitters in WA are fully booked to do the conversion until may next year, and are refusing to answer any calls,
LPG tanks can only be fitted to a certain types of car, in order for a car that hasn't got a plan for LPG, i believe they have to do a crash test with one in the car, (may not be right there, just what i read in the paper)
realistically, the estimate to actually save money after the conversion is expected to take around 5 yrs with the inflated prices, also, PLG prices are expected to rise somewhat as demand increases, (i doubt that one)
this however is (to me) common sense:
turbo + LPG conversion = turbo eats up LPG and you have to refill much more often,
LPG puts more strain on all engines bescause the ignition isn't as resonsive as petrol, this is the case with NA engine, imagine how much strain a turbo would put on it?
now here's food for thought...
LPG conversion = ~$4000
turbo + LPG increased consumption = more fuel purchases
engine problems to ensue as time goes by = billions and billions of money
long run savings = nothing worth mentioning
IF you want to save on efficiency, and don't give a crap about power,
RB20DE engine = ...$800 i would think?
fuel consumption = good
conversion costs, = $2
savings in long run = billions of moneys + save your dignity of not having a LPG powered car.