I've been using Nulon 10W40 (I think??) full synth for my last couple of changes. Seems like nice enough oil, but I did get a little evaporation over a time. (I change my oil every 7500Ks now) I say evaporation, because it's not leaking it, and as far as I know it's not being burnt either - exhaust is too clean for that.
Some people will say to only use Mobil 1 - Meh, well it's good oil - but it's a damned rip-off! And with the Alloytec sump capacity at around 6.5 litres, a change with Mobil 1 is getting pretty spendy! I get a 6L container of Nulon for about $55-60, and an additional litre bottle to top it off. Gives me a half litre to top it up with later.
Make sure when you change the oil to do the filter as well. The filter in the Alloytec is a pretty poky little thing - not all that much room for the filter media itself..... so I don't see it being as efficient over longer periods as a bulkier one. They're cheap anough anyway from Supercheap or Ricebarn....