you will use slightly more lpg than petrol (think it`s about 10-15% more),but don`t quote me,slight lose of power to,but i dought you will notice it

it will run a turbo car,no probs

as said above you get what you pay for,cheap systems=crap

i had my bm 540 done and it cost me nearly £2500

for me it`s worth every penny,averaging 21 to the gallon
if it was solely petrol i couldn`t afford to run it,but at 39.9p a litre it`s like running a normal modern car

hope this helps
dave