LPG works well. very well. If you are considering budget you just need to look at purchase price and fitting of petrol/lpg and then the cost of a diesel machine. then you need to do a quick tot up of your running costs for both using the manufacturers figures and how long you will keep the car etc. There are alot of scare stories about lpg but alot of this is just hot air from a oil industry bias. A good lpg installation will not be noticeable to anyone but you the car will be the same but half the cost to run...
Alfa Romeo 156 SW 1.6 LPG Custom, Alfa Romeo 146 1.4TS, Alfa Romeo 33 1.3