Finally I have managed to get my baby the NLG conversion! No more starting or ignition problems! The installation is mainly simple: In the trunk there's a toroidal NLG tank (38 liters capacity) with a filler cap drilled on the right fender. From there a gas line and some control wires from the tank's valve and fuel pump to the engine compartment. There it's installed an electrovalve after a relay, a gas reductor, heated by water lines from the climate system, and a mixer into the air-filter housing. Here's the schematic on the internet (I'll post pictures - when I'll have a camera available - of the actual installed system):
Here I've scanned the gas mixer installation manual for this system:
More photos will follow!