by HyRax » Tue Mar 04, 2014 6:50 pm
The 2.5 does have some good poke in it, especially if you have a facelift model because they can be tuned to provide an extra 10% in power and torque and can go very well if you keep the revs above 3,000rpm.
That said, the 3.0 can be easily tuned into better-than-stock-WRX power territory with no engine mods, but some 3.0's are known to consume oil.
Fuel consumption on both models is pretty consistent.
The 2.5 manual only comes with a five speed manual gearbox, but the ratios are not too short and not too long to bother you, easily fitting most of your comfort driving at the speed limit within 3,000rpm to save fuel. In the 3.0 auto even with flappy paddles, it's very laggy and not immediately responsive when you put your foot down unless you drive in Sports Sharp mode all the time and empty your tank that much quicker. I can't speak for the pre-SI models.
Ultimately it depends on what you are going to do with it. If you are going to tow stuff and regularly go camping and do mild offroad, I'd go the 3.0 auto Outback. If you are staying in the city all the time with occasional highway drives out country way and generally won't be giving it a lot of stick but need to be able to overtake grandma occasionally, then the 2.5 will be a better buy, will probably save some fuel and you save boatloads on insurance too.
As for parts, Liberty and Outback parts are for the most part interchangeable, but generally the bits that are close to the engine or exhaust are not interchangeable between turbo and N/A models (eg: front swaybar is shaped differently to avoid knocking on the exhaust which has different paths to each other), but everything else pretty much is. Some parts are also designed specifically for wagon or sedan, so look out for that too.
I was going to procrastinate, but I put it off...