Rowan,
It's possible that with 230,000kms your friend has an engine in decent condition, although it's probably due for at least a compression/leakdown test and likely some maintenance work. That's about 140,000 miles, correct?
If he wants to drop in a new engine for turbocharging, the 3.2 liter S52 converted to OBDI is a monster. Not sure of the legality of this down under. It's technically illegal in the US, but in FL no one cares. CA is different.
However, an engine swap combined with a turbo isn't a wise choice economically unless he has a lot of irrevocable upgrades or is stuck with the 1993 325.
An FDRX7 would be a great choice, or an M3 with AA's turbo kit. He could also look at superchargers such as Dinan's or AA's.
But, since you guys are in Australia, why not a Skyline?
