Kevin: Design-wise, the ALH and the AHU are very similar. They have the same displacement, but small bits are different, such as the way the engine mounts are set up, the turbo is a different type, the oil filter housing is different, and the ECMs are a different design. Either one is very durable.
WVO is not a good thing for these engines, due to the low combustion temperatures in these engines. High temperatures are necessary to consume WVO, so soot and sludge are left behind, which begins a process of degredation that ultimately ends when the engine can no longer develope adequate compression pressure, and will consume vast quantities of oil as the rings lose their ability to seal, because they seize in the piston as the sludge formed acts like a glue. The only option at that point is a rebuild. A compression test will tell you a bit about the rings and valves.
Unfortunately, without the VAG-COM, it is a bit difficult to determine what the overall running condition of the engine and its related bits are, and impossible to check its running timing, but the car certainly needs to be scanned, and the use of starting fluid needs to stop, or it will get very, very expensive.
-Rich