My last vehicle was a Subaru ('99 Outback Wagon) and I seriously considered getting a newer one when it was time to replace it. In terms of reliability, I never had any problems in 4 years/80k miles (which were miles 40k-120k in the life of the vehicle.)
Here are a few things to consider:
1. On any Subaru made before about 2001-2002 with the 2.5 motor, head gasket failure is not uncommon. It doesn't happen on every vehicle, but it happens on enough of them that its' something you need to at least prepare for. And of course being a flat-4, there are two head gaskets to worry about. The 2.2 engine (on non-Outback Legacy's and Imprezas) does not have this problem, nor do the later 2.5l motors.
2. While it's true that the Subaru has 7-8" of ground clearance, that's somewhat deceptive because the approach, departure and breakover angles royally suck, especially on the long Legacy platform. The shorter Impreza platform (which includes the Impreza, the Outback Sport and the Forester) are somewhat better here. Also, whereas on a regular 4x4 truck, you might have an axle pumpkin at 7" or so, you won't have much else. On a Subaru, OTOH, there's all kinds of stuff hanging down there. I had a problem driving my Outback on a muddy road because the rear driveshaft tunnel got packed with mud and dirt and made a hellacious racket when I was driving.
3. Even the Legacy wagon (Outback) is somewhat cramped inside.
4. While Subaru MPG is better than that of most 4x4 trucks and SUVs, it's not that much better. I averaged about 22-23 in the city and 27-29 on the freeway, but then again, I drive like an old lady (cruise control set at 65 on the freeway, etc.) If you drive in a more "spirited" manner expect a corresponding drop in MPG. And mine was bone stock down to the tire size.
A little realism is called for here: By the time you add that lift kit, bigger tires, bull bar, winch, roof rack and spare tire carrier, you have probably (1) come close to maxing out the safe weight carrying capacity of the car (and that's without driver, passengers and outdoors gear) and (2) have probably reduced your MPG to 20-24 mpg tops.
Finally, if you actually are driving a lot of those 2 or 3 level trails, you are putting a lot more stress on that unibody structure than it was ever designed to take.
And 20-24 mpg? I get that with my V-6, 4wd Tacoma! In fact, I routinely get 20 in mixed city/highway driving, and in sustained highway driving I typically get 22-24, depending on how much I'm hauling and how fast I'm driving. Plus the Taco can carry a hell of a lot more gear, is much more rugged (body-on-frame construction) has 31" tires, low range, and true off-road capability. In fact, the only way the Subaru beats me is in the fact that it can carry more passengers than I can.
So, while the Macho Subaru is a cool idea and a fun project, I think you have to ask yourself where do you reach the point of diminishing returns? And what is the objective? If it is to actually have an economical and reliable off-road vehicle, then a small pickup or SUV probably accomplishes that with nearly the same MPG as the Subaru. OTOH, if the objective is to see what you can do with a Subaru, then go for it. Just don't expect spectacular results.
