The setup cost $3300 after the government rebate. The people who installed it (Auto Gas Injection, Frankston) said they didnt have any problems setting up the system. They said liquid injection runs best when you have a petrol system that utilizes electronic sequential injection which fortunately for me the r33 s2 does have.
The economy figures i am getting are as below (l/100km):
PetrolLPGMax12.0215.40Min11.2711.44Avg11.6514.11
Note: Petrol consumption was when it was running on stock boost and lpg is when it was tuned to 11psi.
Basically it shows when the car is driven "responsibly" your fuel consumption on lpg is only a few % greater than running on petrol. But when you thrash it your consumption can be over 20% more than running on petrol. I have been told lpg burns a lot faster when the car is being driven hard as it has a lower energy value compared to petrol. But still when you look at the average it works out approx to be the same running costs as say a toyota yaris but with 190rwkw!
I hope this helps.
Cheers,