It is NOT difficult.
Do not believe what you are told (in Australia) re converting an air cooled vehicle. The gas can be heated via 2 methods:
a) tapping in to the oil lines and using the oil, or
b) inserting a rod in to the exhaust to heat up the gas as it passes over the end of the rod. In the UK this is an "off the shelf item"!
The latter is the preferred method. This is very, repeat VERY common in the UK amongst Kombi enthusiasts. Yes it is more difficult in the confines of a Beetle but not in a Kombi.
Check out the LPG conversion forum on this page:
http://p067.ezboard.com/bclub8090chat
A lot of the info relates to converting the watercooled T£ (or T25 as its called there) but there is plenty of info on air cooled conversions too.
There are plenty of other sources of info that the folk on 80-90 can direct you toward.
Don't be put off by the nay sayers. It is a conversion that works very well.
Good luck and contact me if you need any help. I converted my Syncro to run on LPG myself when I lived in the UK.
Cheers,
Andy.
[Edited on 18/5/2005 by type2nut]