1 Lucky Texan

kinda dodging the direct question to mention that SeaFoam has a spray can with a special u-turn nozzle designed to use in-car. Look for videos how to use it.

seems like input shaft bearing symptoms.

^^^^ yep, take your own alt, or maybe a used one from a wreck or car-part.com and have it rebuilt by someone local. or check into DBElectrical or maniacelectricmotors .

I think I recall reading the user @GeneralDisorder has shipped a few cars. maybe he has a company to recommend?

I wish we could find an NTN discounter.....

I believe the cable from the KS is shielded, maybe you have a grounding problem. excessive carbon buildup in one or more combustion chambers could lead to excessive knock. maybe pull and examine the spark plugs for carbon??? I'm about out of ideas.....

you could try the Subaru Coolant Conditioner (rebranded Holt's Radweld) - 1 bottle only, installed per directions ONLY.

local tuner gets new FEQ brand 'HD' (which only gets you better rubber boot at the wheel end 'I THINK') from some distributer called Worldpac, but I have seen them offered at Amazon, etc. I think. Might be worth running backwards from the FEQ website - maybe find the part number for the HD axle for the car in question, then find a retailer...? Does anyone still get axles from Raxles ? VW guys seem to like them.

you may need to pull the battery cable for a few minutes or clear the code with a scanner. Or, you may not see the code clear for 5-6-7 drive cycles.

hmmmm... not sure about this but, just chiming in to mention I have read of the Aussies building sand rails with soob engines. they may have some interesting adapters or components.

if you protect sensitive parts in the area, you could use a propane torch (the blue wrench!) to heat cycle it a coupla times. Maybe the last time, carefully spray it with PB Blaster or other penetrant . As it cools, it may pull some penetrant deeper in.

If the system is working correctly, it is 'self adjusting' . This is a very common failure on 15+ year old cars. Many people have fixed this. Of course, it's possible to have more than one problem, it's possible to get a bad new part, but, it is not anything special, expensive or requiring a visit to a dealer.

'virgin vent'?

I think for an enthusiast with some time/money on their hands, or someone with a race whip, there may be some utility in experimenting with gear lubes - maybe moreso if you live in the SW or extreme north, further tailoring the lube chosen for extreme temps. but, the OEM lube (Extra-S ? made by Idemitsu I think) or a name brand non-synth lube probably works fine for most people. If you have a leaky, or older car and no money to spend, there is a synth-BLEND at walmart (supertech ?) that folks feel is a good value. Local tuner shop (the guys that fixed my trans) use Amsoil Severe Gear 75W90 . It's still in there. feels OK to me. BUT, I also had to rebuild my shifter and since putting in new poly bushings, kinda have the itch to try something new. But, not driving the car much right now - lost my job. I also have a feeling the trans prefer quicker shifting, seems like I get more balking if I'm slow about shifting - could be a lots of factors really. if you want to go down a rabbit hole - try this link; https://forums.nasioc.com/forums/showthread.php?t=920674

I have had 'spurious' codes thrown 3 times on my 2 soobs, (even put my WRX into 'limp' mode) bad batteries everytime but, I suppose other issues like charging system or poor grounds or 'dirty' connections, etc. could cause the same type of problem. And often codes are thrown due to issues unrelated to the 'official' definiton/description of the code's involved. That is, just because a rear O2 sensor has 'catalytic converter efficiency' in it's description, doesn't necessarily mean the catalytic converter is bad.

If someone put synthetic lube in that 5spd you dove, that could explain some 'balking' when shifting. Because the trans and it's synchros share housing/fluid with the front diff, non-synth GL-5 is usually best. Full synth causes the synchros to be too fast or something...MANY people tinker around with finding their favorite 5spd lube. There's a huge thread devoted to the issue at NASIOC.

after 17 years of ownership, today I discovered that the DS window defogger vent in our '03 OB can be flipped to direct upwards to the windshield!!!

one or 2 people have swapped-in a 5spd or, better, a Legacy Spec B 6spd into an H6. the H6's xtra power would probably be a death knell for the 5spd. If you're just on flat-ish/dry-ish gravel/dirt, 5spd 4cyl probably OK. others here will have actual off-road experience for your questions. I mostly wanted to warn you about 5spds - they have a but of a poor reputation. Certainly more-so among WRX owners - they start tuning the car and then complain when the clutch or trans fails. I paid $2000 to fix my trans(2nd gear is cut onto the main shaft w'ever), wish I could have afforded to just get a 6spd put in but, alas, I couldn't justify it at the time, plus all the other internals looked great (the tech said) and - under 70k miles too.

^^^^^ that, good post.

maybe a bigger oil pump AND higher viscosity?

you can get contacts and even plungers to rebuild starter solenoids. There's even videos to show you how.

everything I have read points to the 4EAT being much superior off-road to the 5spd. just my opinion(also, my WRX's 5spd removed all the teeth from 2nd gear - under 70K miles, NO power mods)

the issue at my house, we really don't need 3 cars, but I don't want to give-up either of the ones I have. if I'm honest with myself, the WRX makes the least sense to keep, but it is the one I would miss the most. I do think shopping 'soon' could better than 'later'. If a vaccine becoms widely available, some types of products/services could experience a 'run' resulting in shortages. Although, I have also read that there is a glut of used cars (repos???) and that may keep prices down???

some folks would go to car-part.com and just slap in a used trans instead of busting inside the trans.

There has to be some, well, 'hope', that there will be 3rd party sources for electronics replacement/repair/refurbishing - or some kinda standalone replacements for newer cars. average age of cars on the road is steadily going up so, perhaps the trend toward robust longevity will continue?