if you have to ask you can't afford it
Agree with the 20L/100 urban running. My 94 Vogue LSE seldom betters this. Still, I mostly drive the guzzler 800m to the railway station which is well within (just) the range of the 90 litre tank. Ha ha! It's a horrible walk. Thus keeping the beast continues to be affordable even if petrol tops $2/litre which it surely will, very soon, thanks to the essentially pacific nature of the middle east and Juliar's moronic carbon dioxide sin tax. Spending $10k plus on a diesel conversion is truly for the courageous. You might as well do it properly and buy a new 3 cylinder 50MPG shopping trolley for only a few grand more.