I'll caveat this with depending on where you live at - this could be a deal breaker. As far as I know, there is no CARB compliant LPG kits available. They have LPG "enrichment" kits, that help boost power with appropriately modded, high compression and/or forced induction engines (LPG has about 100-110 octane rating). But most are designated for pre-emissions cars and trucks, preferably with a carburetor.
From what I've seen in my area - the pro's and con's:
PROS
- cheaper fuel costs, typically in the low $2 per GGE (Gasoline Gallon Equivalent)
- burns cleaner, less emissions
- less soot means potentially longer oil change intervals
- retain gasoline burning ability for flexibly fueling
- higher capacity tanks are being utilized now for range and safety
- lots of kits available for carburetor applications, starting to grow for fuel injected apps - some now with EPA approval
CONS
- high initial cost to convert (kits typically in the $1000+ range, $3000+ installed, cheaper for carb'd applications)
- potentially cannot be smogged (No EO#, no referee)
- loss of some power being not as energy dense as gasoline
- lack of LPG filling stations in some areas
- range limited to tank size
- potential safety issue if installed incorrectly, more maintenance required for the plumbing (200+ PSI)
- possible engine damage from the "enrichment" type systems