Which engine oil should I use for an LPG conversion?

I am unsure of what engine oil to use for my 1999 BMW 316i compact. It has a 1.9 engine converted to LPG and has done 189,000 miles. Haynes manual says 15W 40. The online 'tap in your reg' section give...

Can I convert my Nissan Murano to LPG?

Is there any problem in converting my 2005 Nissan Murano 3.5L CVT to run on LPG? I have heard that the valve seats could wear prematurely - can this be avoided? If OK, what system would you recommend?

Range Rover 1999 4.6 LPG

It looks very much as though my HG (or worse) has cracked. Does anyone know the best course of action? Undriveable now, the thing overheated and the rad pipe blew, that's replaced but creates way too much...