Numbchux

AFAIK, the warranty for a DIYer is generally 30 days, and they just give you another engine. And they expect to get theirs back in exactly the condition it was sent. As such, I waited to order mine until I was 100% ready to put it in. I had all my gaskets, timing components, etc. on hand. The old motor was out with the intake manifold off and ready to use. So I swapped everything over (kept everything I removed from the JDM engine in a box) and was ready to start test driving about 3 days after it arrived.

I've bought one, and plan to buy a couple more. I just bought on eBay, paid with a Credit Card through PayPal. This gives me 3 separate avenues for accountability/charge dispute. Read the sellers feedback history, make sure they have a decent history, and have been selling engines for some time (I noticed at least one seller that had a decent rating, but almost exclusively on small parts...). Best practice is to swap the intake manifold and all wiring over from the old engine. The link that @idosubaruposted is for a bare, new shortblock. This will have a 1 year warranty. Call your local dealership and ask about remanufactured shorblocks. These are about the same price, but come with oil pan, pump, water pump, thermostat, etc, and come with a 3 year 36k mile warranty.

Cruise control is disabled whenever the check engine light is on, in those cars. Pretty long and well-documented diagnostic process to the P0420.

Should be largely the same. Use STi Head gaskets, just like the USDM 2.5s.

Aisin is the way to go if you want a "kit". I use Mitsuboshi belts, NSK or Koyo bearings, and an Aisin tensioner. Requires more homework to find all the right part numbers (I usually look up OEM # by VIN, and cross reference from there), and sometimes ordering from multiple sources (I've been using CarID for the last few sets, but I think I've gotten the tensioner from RockAuto). Don't think I've bought a water pump in 10 years or more...

I've heard of people machining/redrilling the stock hubs to 4x100. That's probably your best bet, if that's the size you want. It gets difficult as it begins to clash with the bosses for the rotor mounting bolts. You're currently running a 7" wide wheel with 4.5" of backspacing (meaning 1" of negative offset!), yea, that's not going to fit well. A stock Toyota or Nissan 6" wide wheel will fit much better. It is certainly possible to have new hubs made, but my understanding is cutting the splines is extremely expensive. Someone had a run of 5 lug rear hubs made not too long ago. They were manufactured overseas in large-ish quantities, and they were still spendy. I suspect having 2 pairs made (they are different front and rear) will be many many thousands of dollars.

I'm not sure replacing the part would have a different effect. It's my understanding that they are very sensitive. My mom has said many times that she can only put in about a 1/2 quart when the light comes on before it's at the "Full" mark. She keeps a paper funnel tucked in next to the battery....

Off the top of my head, 4-cyl AT Outback and (I think) GT are 4.444 axle ratios. H6 Outback is 4.111. So you might have to swap rear diffs, as well. www.car-part.com is a very useful tool for finding used parts.

I've seen many broken, especially on crashed cars, but not always. Get a new one. I bought a Subaru one for our Outback, so it couldn't have been too expensive. And they are available aftermarket.

Yes, that car has an oil level light, and an oil pressure light. If the oil pressure light comes on on the freeway, the engine is done. If it flickers a little bit at hot idle, you might be able to save it, but at rpm and load....no. We discovered with my mom's 12 Impreza that the level light comes on pretty early, sometimes the level doesn't even read to the low mark on the dip stick, and only needs about a half a quart to read "full". Hers is a bit of an oil burner, so she's gotten used to carrying oil and a funnel.

OEM water pumps very rarely fail. Not a chance I would replace it at 120k miles. I buy a Mitsuboshi belt, NSK idlers and Aisin tensioner separately. Anything beyond that would be as-needed.

Yep, not uncommon problem. Nut too loose, and/or incorrect washer placement underneath it. Strips the splines in the hub out.

I just did some quick math (what can I say, slow afternoon at work...). My mom's 2012 Impreza uses a quart of oil about every 750 miles. When I worked at the dealership, we had many customers reporting a loss of 3-5mpg after receiving a new shortblock (with tighter rings). Over 750 miles, with fuel costing $3/gallon, a drop from 35mpg to 32mpg is about $6. Depending on the oil you're using, you could easily come out ahead. If you're getting 4k miles to a quart, that difference jumps to $32.13. If you can find a quart of oil for $32, you're going something wrong. So yea, it's cheaper to risk a little extra wear on your cat than replace your engine.

They call for 0W20. That's right in the heart of the oil consumption class action lawsuit that was filed against Subaru. Subaru extended the warranty to 100k in response. There are 2 oil lights. A low oil level light, and a low oil pressure light (the older cars only had pressure, and interestingly the first few years of FB engined Foresters, most Forester owners just drove them until they blew up, whereas Impreza and Leg/OBK owners got the warning light). The level light comes on kind of prematurely, as the engine is usually less than a quart low. But this prevents catastrophic damage. My mom bought her 2012 Impreza with about 20k miles on it, it's over 200k, now. It has a salvage title, so was not eligible for a free engine, so she keeps a quart of oil in the trunk, and a funnel tucked in next to the battery. I just found out this week that she's down to ~750 miles per quart, so I advised her to switch to synthetic 5W30. She has seen a P0420 a couple times, so the cat is probably not happy with the hundred + quarts of oil that has gone through it,

I was trying really hard. It's a shame I wasn't able to follow it through, but it was just too rusty. Nothing wrong with sleeves, IF the spring rate and damping match well. I've been running a pair of those same sleeves, with softer springs, in the rear of my Celicas for nearly 10 years (across 2 different cars). They ride excellently.